PVE hero recommendations

Magic is everything my friend

I love absolutely using Arvis. He can quad ploy and heal the team, and he has decent stats and a good supportive special naturally.

Reinhardt (who Senpai was referring to in his comment) and Nino are ones who come to mind as being solid heroes in PVE. Others that come to mind are Soleil and Cordelia as sweepers.

Dragons : Adult Tiki, Nowi. (Good Tanks with DC)
Blade Mages: Nino, Tailtiu, Tharja (Can deal tons of damage, with +spd iv's if possible)
Raven TA: Henry, Robin, Cecilia. (Bow checks)
Flyers: Cherche, Cordelia, Caeda (+Atk), Clair (+Atk) (Good anti armour units and Cordelia has galeforce)
Cav: Xander, Camus. Titania (DC units and Titania is good for tactics and can deal with nowi)
Armors: Effie, Sheena, Gwendolyn, Draugh, strong units but need a lot of SI.

Raven helped me clear both abyssal Maps lately, and is also very versatile and has a very balanced stat spread. Basically any hero Who can make good use of galeforce

For PVE, you can get a ton of mileage from a healer with Pain (w/dazzle effect), Savage Blow C skill, and Savage Blow seal.

Set them up with dancers and they can attack without being countered, and will do 24 dmg to enemy and everyone within two spaces after combat.

You don't really need to +10 these either.

Azama, in my opinion. With Pain+++ and Fortress Defense he becomes nearly the ultimate support. Don't expect him to kill things, but he'll tank nearly everything physical and as long as the rest of your team can hit for 1 point of damage he can enable just that. He's super useful.

Another one I'd reccommend is Sophia. With proper building, (though expensive) with Raorowl, Close Counter, QR, Atk Smoke, etc., she becomes an absolute monster of a mixed tank. I don't have one myself, but I've used my friend's in GC/RD and she'll tank multiple things of every type and color. She's pretty awesome, but she's quite expensive to get there.

A few types that seem most effective to me are:
- blade tomes and certain other ranged nukers: Nino, Tailtiu, Tharja, B.Tharja, B.Lyn, B.Cordelia/S.Takumi (brave bow), Reinhardt. Most of these are buff-dependent and don't require merges if you play them right. Work well with dancers.
- debuffers: smoke daggers, Peshkatz, maybe Felicia with atk smoke. Levels the playing field a bit against the ridiculously inflated stats
Galeforcers, because you'll be outnumbered: Cordelia, Raven, Karla if you have her.
- DC super mixed-tanks, especially those that sustain with aether, especially those that avoid some doubles: Nowi, some builds of Fae, B.Ephraim, other armours. My preference when up against enemy dancers, since they will probably survive anything thrown at them.

I'm surprised nobody has mentioned Brave Bow units. I get a lot of use out of my LA!Roy with BB+, Death Blow, and Desperation/Brash Assault - pair him with Wings of Mercy dancers and it's EZ Clap. Technically +ATK Leon has the highest Atk of any non-seasonal bow unit, so that's probably the most accessible option. Jamke will come in right behind Leon with one less Atk than a +Atk Leon.

Cherche can run something similar but with Brave Axe instead. Here's an example of supermerged 4* Cherche clearing Abyssal L!Robin with three dancers to support:

https://www.youtube.com/watch?v=4-aqy8ehY1o

A lot of mentions of some good units here.

I'm just going to add Olivia because a lot of the time for PvE it's useful to have a dancer. She has a pretty decent stat line as a bait/combat unit too.

Klein has a great default kit if you don't already have a bow unit. For specific maps, you can give him a breaker for whatever weapon type you're having trouble with.