So threw together something for Brawl in Arena, it's Gruul and makes non human creatures stand out for extra value. First lets go over the only human in the deck. Robber of the Rich is such a value card with haste, reach, potentially stealing from the opponent, or at the very least exiling something that can be used against you is a huge bit of value that is worth not getting a +1/+1 counter from the commander.
Because removal is a thing, we want to be able to ramp out Grumgully, the Generous and other threats as soon as possible. This means having most of nonhuman ramp currently available, Domri, Anarch of Bolas can be ramp, removal and pumping up the team. Dryad of the Ilysian Grove, Gilded Goose, Ilysian Caryatid, Paradise Druid,, and The Great Henge can all help fix and improve mana, with the henge doing double duty by pumping with an additional counter and drawing cards.
For synergy, we have a few cards that help out specifically with the nonhuman buildup of the deck. Barge In is an ok pump spell, but for giving most of the team trample at instant speed can be game winning. Ferocity of the Wilds doesn't seem like much, but when you have stuff spitting out hasty tokens, getting counters from Grumgully and an additional power boost and trample, it really brings the deck together. Fling while not specific to nonhumans can be decent for that last bit of reach, or blanking an opponents removal spell. Because of this, I went with Fling over Thud.
Tokens are also a big theme here. Now for pumping up, Rhythm of the Wild and The Great Henge only care about nontoken creatures, but both Renata, Called to the Hunt and Grumgully, the Generous will pump both token and nontoken creatures. Anax, Hardened in the Forge can be great, a fun target for Barge In late game, or the tokens made from it will also be 2/2 if you have your commander out making boardwipes decidely painful. Chandra, Acolyte of Flame is a great card for the converted cost, and can end up putting pressure on the opponent with elemental tokens or reusing some instant or sorcieries as needed. Grim Initiate gets a bonus from its amass, along with early pressure. Krenko, Tin Street Kingpin puts in a lot of work with any counter or power enablers. The bonus when Krenko enters with a token, then taps, adds a whole lot of other tokens can be the game on its own. Legion Warboss is good for almost the same reason, but just solid turn after turn pressure. Be careful though, if the opponent has a bigger lifelink creature, that can be a problem. And possibly one of the most swingy token producers in here is Scampering Scorcher. With Grumgully out, it represents 6 power spread over 3 bodies with haste for 4 mana which is not bad. With some other pump spells and abilities, this card can come out of nowhere and take over the game.
Overall, this deck has been fun for arena, but a bit expensive for my taste in MTGO. Please feel free to leave a comment or suggestion. If you do decide to pick up this deck, hope you enjoy it.