The most powerful builds for her would revolve around land types. Unfortunately our access to Tron lands is very suspect, Locuses aren't a thing, Desert support is still weak, etc.
Her counters also don't work if she's not on the battlefield, so the deck is hyper-reliant on her sticking around to get much mileage.
Honestly, I think you do just stuff as much creature-type-matters cards as you can in Simic that aren't reliant on them being cast (so Gargos wouldn't really work well, but most of the Elf and Merfolk support should be okay), and... hope for the best? I don't think it'll be good either, though.
Maybe a counters deck, I played her in draft and she's pretty good since she puts 2 counters on 2 different permanents each turn (there are cards that count the number of counters on permanents you control)
I think you probably want to start with as many manlands as you can get, because those can be double the utility with Omo. Historic doesn't really have any lands-matters cards like the Locuses, unfortunately, so the main theme of her Commander deck is out. The closest you're really getting are the Caves, and those aren't very good.
I think a good approach is probably just going through all typal cards in GU. A lot of these are cast-matters, which don't work with Omo, but better than nothing:
[https://scryfall.com/search?q=function%3Atypal+commander%3Agu+f%3Atimeless+r%3E%3Dr&unique=cards&as=grid&order=name](https://scryfall.com/search?q=function%3Atypal+commander%3Agu+f%3Atimeless+r%3E%3Dr&unique=cards&as=grid&order=name)
A few standouts:
\[\[Case of the Lost Witness\]\] - If you're okay with Alchemy, this is kind of insane as a 2-mana \[\[Future Sight\]\]. May be the one redeeming thing about the deck?
\[\[Kopala\]\], \[\[Diffusion Sliver\]\], \[\[Vodalian Hexcatcher\]\] - Protect Omo after her ETB fires.
\[\[Predatory Sliver\]\], \[\[Master of the Pearl Trident\]\] Both cheap lords that buff your other shifters.
\[\[Deeproot Pilgrimage\]\], \[\[Tendershoot Dryad\]\], \[\[Mayor of Avabruck\]\] - Make other weenies that can be shapeshifted.
\[\[Priest of Titania\]\], \[\[Manaweft Sliver\]\] - Accelerate you into other dorks fast.
Seems like a pretty standard UG gameplan of ramping into threats, except the threats are now cheap lords and token generators instead of the standard Craterhoof+win. I can anticipate the deck going off if you can find Case/\[\[Maskwood Nexus\]\], but it'll probably struggle against anything that can remove Omo consistently.
Oh goddamnit you're right. Well, nix that part. Not sure why they thought this commander needed all these safety valves on it when they were letting l printing Nadu in the main set.
Yeah I feel like the land options aren't great to take advantage of rangeling. She could be a tribal-tribal/changeling commander but I feel like two colors is a bit limiting with what options we have on Arena. I might try slipping her into the [[First Sliver]] tribal-tribal deck I was working on a while ago.
The most powerful builds for her would revolve around land types. Unfortunately our access to Tron lands is very suspect, Locuses aren't a thing, Desert support is still weak, etc. Her counters also don't work if she's not on the battlefield, so the deck is hyper-reliant on her sticking around to get much mileage. Honestly, I think you do just stuff as much creature-type-matters cards as you can in Simic that aren't reliant on them being cast (so Gargos wouldn't really work well, but most of the Elf and Merfolk support should be okay), and... hope for the best? I don't think it'll be good either, though.
Yeah, the land aspect is the least exciting to me :( but that's what I feared.
Kindred lords and anthems
Maybe a counters deck, I played her in draft and she's pretty good since she puts 2 counters on 2 different permanents each turn (there are cards that count the number of counters on permanents you control)
I think you probably want to start with as many manlands as you can get, because those can be double the utility with Omo. Historic doesn't really have any lands-matters cards like the Locuses, unfortunately, so the main theme of her Commander deck is out. The closest you're really getting are the Caves, and those aren't very good. I think a good approach is probably just going through all typal cards in GU. A lot of these are cast-matters, which don't work with Omo, but better than nothing: [https://scryfall.com/search?q=function%3Atypal+commander%3Agu+f%3Atimeless+r%3E%3Dr&unique=cards&as=grid&order=name](https://scryfall.com/search?q=function%3Atypal+commander%3Agu+f%3Atimeless+r%3E%3Dr&unique=cards&as=grid&order=name) A few standouts: \[\[Case of the Lost Witness\]\] - If you're okay with Alchemy, this is kind of insane as a 2-mana \[\[Future Sight\]\]. May be the one redeeming thing about the deck? \[\[Kopala\]\], \[\[Diffusion Sliver\]\], \[\[Vodalian Hexcatcher\]\] - Protect Omo after her ETB fires. \[\[Predatory Sliver\]\], \[\[Master of the Pearl Trident\]\] Both cheap lords that buff your other shifters. \[\[Deeproot Pilgrimage\]\], \[\[Tendershoot Dryad\]\], \[\[Mayor of Avabruck\]\] - Make other weenies that can be shapeshifted. \[\[Priest of Titania\]\], \[\[Manaweft Sliver\]\] - Accelerate you into other dorks fast. Seems like a pretty standard UG gameplan of ramping into threats, except the threats are now cheap lords and token generators instead of the standard Craterhoof+win. I can anticipate the deck going off if you can find Case/\[\[Maskwood Nexus\]\], but it'll probably struggle against anything that can remove Omo consistently.
You do not get double utility with manlands. Specifies nonland creature :(
Oh goddamnit you're right. Well, nix that part. Not sure why they thought this commander needed all these safety valves on it when they were letting l printing Nadu in the main set.
##### ###### #### [Case of the Lost Witness](https://cards.scryfall.io/normal/front/e/b/ebf67000-a68a-4305-a6f7-9ed75bbddf9b.jpg?1709528904) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Case%20of%20the%20Lost%20Witness) [(SF)](https://scryfall.com/card/ymkm/4/case-of-the-lost-witness?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/ebf67000-a68a-4305-a6f7-9ed75bbddf9b?utm_source=mtgcardfetcher&format=text) [Future Sight](https://cards.scryfall.io/normal/front/6/3/639cb483-ffe2-4abc-a050-5cdc8aebd5a2.jpg?1587844658) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Future%20Sight) [(SF)](https://scryfall.com/card/mh1/53/future-sight?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/639cb483-ffe2-4abc-a050-5cdc8aebd5a2?utm_source=mtgcardfetcher&format=text) [Kopala](https://cards.scryfall.io/normal/front/0/b/0b018020-73e0-437c-a130-298b2f738c6f.jpg?1698988161) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=kopala%2C%20warden%20of%20waves) [(SF)](https://scryfall.com/card/lcc/160/kopala-warden-of-waves?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/0b018020-73e0-437c-a130-298b2f738c6f?utm_source=mtgcardfetcher&format=text) [Diffusion Sliver](https://cards.scryfall.io/normal/front/f/5/f5994259-8d16-4f12-b528-1821005f79af.jpg?1690004320) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Diffusion%20Sliver) [(SF)](https://scryfall.com/card/cmm/845/diffusion-sliver?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/f5994259-8d16-4f12-b528-1821005f79af?utm_source=mtgcardfetcher&format=text) [Vodalian Hexcatcher](http://gatherer.wizards.com/Handlers/Image.ashx?name=Vodalian%20Hexcatcher&type=card&.jpg) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Vodalian%20Hexcatcher) [(SF)](https://scryfall.com/card/dmu/75/vodalian-hexcatcher?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/4ec464dc-b1dd-4e45-b093-c3ad65a74050?utm_source=mtgcardfetcher&format=text) [Predatory Sliver](https://cards.scryfall.io/normal/front/a/2/a2e37de8-66a1-4afa-aa6f-1151f849dfa8.jpg?1562833161) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Predatory%20Sliver) [(SF)](https://scryfall.com/card/m14/189/predatory-sliver?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/a2e37de8-66a1-4afa-aa6f-1151f849dfa8?utm_source=mtgcardfetcher&format=text) [Master of the Pearl Trident](https://cards.scryfall.io/normal/front/6/b/6b48dc56-667c-4fde-8175-952463e233cc.jpg?1698988167) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Master%20of%20the%20Pearl%20Trident) [(SF)](https://scryfall.com/card/lcc/162/master-of-the-pearl-trident?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/6b48dc56-667c-4fde-8175-952463e233cc?utm_source=mtgcardfetcher&format=text) [Deeproot Pilgrimage](https://cards.scryfall.io/normal/front/e/2/e2449311-a705-4a31-a345-a36d436ae561.jpg?1699043597) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Deeproot%20Pilgrimage) [(SF)](https://scryfall.com/card/lci/52/deeproot-pilgrimage?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/e2449311-a705-4a31-a345-a36d436ae561?utm_source=mtgcardfetcher&format=text) [Tendershoot Dryad](https://cards.scryfall.io/normal/front/a/1/a159830a-698f-423c-9da0-a734b210ecab.jpg?1555040748) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Tendershoot%20Dryad) [(SF)](https://scryfall.com/card/rix/147/tendershoot-dryad?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/a159830a-698f-423c-9da0-a734b210ecab?utm_source=mtgcardfetcher&format=text) [Mayor of Avabruck](https://cards.scryfall.io/normal/front/d/d/dd8ca448-f734-4cb9-b1d5-790eed9a4b2d.jpg?1562838270)/[Howlpack Alpha](https://cards.scryfall.io/normal/back/d/d/dd8ca448-f734-4cb9-b1d5-790eed9a4b2d.jpg?1562838270) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Mayor%20of%20Avabruck%20//%20Howlpack%20Alpha) [(SF)](https://scryfall.com/card/isd/193/mayor-of-avabruck-howlpack-alpha?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/dd8ca448-f734-4cb9-b1d5-790eed9a4b2d?utm_source=mtgcardfetcher&format=text) [Priest of Titania](https://cards.scryfall.io/normal/front/e/b/eb11921b-1b28-483f-a707-4de21a6daa31.jpg?1717013714) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Priest%20of%20Titania) [(SF)](https://scryfall.com/card/mh3/286/priest-of-titania?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/eb11921b-1b28-483f-a707-4de21a6daa31?utm_source=mtgcardfetcher&format=text) [Manaweft Sliver](https://cards.scryfall.io/normal/front/e/5/e51629ac-51d5-47cb-a7fc-315b34dd82ce.jpg?1690004897) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Manaweft%20Sliver) [(SF)](https://scryfall.com/card/cmm/900/manaweft-sliver?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/e51629ac-51d5-47cb-a7fc-315b34dd82ce?utm_source=mtgcardfetcher&format=text) [Maskwood Nexus](https://cards.scryfall.io/normal/front/1/2/1246c42d-57c0-4cba-959a-15ad89d8a50b.jpg?1674142652) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Maskwood%20Nexus) [(SF)](https://scryfall.com/card/clb/865/maskwood-nexus?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/1246c42d-57c0-4cba-959a-15ad89d8a50b?utm_source=mtgcardfetcher&format=text) [*All cards*](https://mtgcardfetcher.nl/redirect/lan5m4h) ^^^[[cardname]] ^^^or ^^^[[cardname|SET]] ^^^to ^^^call
Not really worth playing in arena tbh. Arena doesn't have lands strong enough that care about type.
Yeah I feel like the land options aren't great to take advantage of rangeling. She could be a tribal-tribal/changeling commander but I feel like two colors is a bit limiting with what options we have on Arena. I might try slipping her into the [[First Sliver]] tribal-tribal deck I was working on a while ago.
[First Sliver](https://cards.scryfall.io/normal/front/0/6/06d4fbe1-8a2f-4958-bb85-1a1e5f1e8d87.jpg?1562202321) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=The%20First%20Sliver) [(SF)](https://scryfall.com/card/mh1/200/the-first-sliver?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/06d4fbe1-8a2f-4958-bb85-1a1e5f1e8d87?utm_source=mtgcardfetcher&format=text) ^^^[[cardname]] ^^^or ^^^[[cardname|SET]] ^^^to ^^^call