I'm also torn between Breloom and Hisuian Decidueye, but will be voting for Hisuian Decidueye simply because what its design is based off of is really cool.
It'll be interesting to see who votes for Chesnaught. As I recall, Chesnaught is the least liked of the final evolutions of the starters from the sixth generation.
Tough call since Grass is my favorite overall type and I happen to like all of these. My first inclination, though, is to say Hisuian Decidueye just because birds are my favorite types of creatures in the world and Hisuian Decidueye's design is a neat changeup from the original Alolan one. I especially appreciate that its headfeathers are more autumnal in the standard model, though its shiny's coloration is cool too.
Breloom is a close second due to its neat design, stats, and access to Spore.
After that would probably be Chesnaught due to its "knight" sort of aesthetic (with Delphox being the mage and Greninja the thief/rogue) appealing to me and the Hidden Ability of Bulletproof that it has, though it has competition from Virizion. I've never used a Virizion on a team as of yet despite enjoying Generation V (I construct teams based on themes and simply haven't added Virizion to one yet.) but I really like its design.
Then I guess Hisuian Lilligant is in last place, not out of any particular dislike, just as a result of process of elimination.
Torn between Breloom and Hisuian Lilligant, but ended choosing Breloom. Idk Breloom is the OG grass/fighting, it has a neat movepool and was just way too ahead of its generation imo. Lilligant is a close second because I love the dancer-like design.
I have to go with Breloom. I definitely have some nostalgia for it due to it being from Gen 3, and it's the Pokemon I both remember and like the most out of the 5 on the poll.
Breloom is my top favorite because I really love its design and it can learn great moves, such as Leech Seed, Spore and Sky Uppercut. It goes from being a small grumpy mushroom to a mushroom raptor that can extend its arm and deliver some seriously fast punches. It has such a cool shiny, too.
I also do like Hisuian Decidueye and Lilligant because they have very interesting designs. Chesnaught is great, too. Grass/Fighting can be both a supporting and offensively strong combination, but it's crippled by having not only the grass weaknesses of fire, ice and poison but it gains the additional weakness of psychic, and it becomes 4x weak to flying and we all know how OP flying types can be, because we have moves like Aerial Ace that so many non-flying mons can learn.
I love Breloom a ton, but I think Hisuian Decidueye might be my new favorite. I think it has a really cool design and inspiration, and I really like its autumn-y color scheme. Plus, I just like owls. Breloom is still a close second for me though. There's just something really cute about it.
I actually like them all! In my opinion GameFreak has yet to make a bad grass/fighting type. My new favorite has to be Hisuin Lilligant! It looks so elegant when it moves. My second favorite is Verizion for many of the same reasons. It’s also just useful in game.