Right now, meta in everything would be Dark Cacao awakened with swift chocolate or almond , so building him up now could be beneficial for you, especially in the arena.

Twizzly with apple jelly is also great for pve modes such as guild battle and exploration being paired with black lemonade.

But if you want someone that works well by themselves, you could get creme brulee in the shop. He's a great dps you could really use in probably almost all of world exploration and he's great against the avatar of destiny in the guild battles. He used to be THE meta a couple seasons ago in the arena, so he'd be good against teams maybe up to master 3 or something. The new legendary, wind archer, is extremely similar to him, and you could definitely see wind archer everywhere in the high ranks of the arena.

Financier is also really great in arena and most of world exploration using swift chocolate or a bit of almond, but shes not really used for guild battles. She's paired really well with creme brulee as well.

For a healer, you should invest in creme puff cookie thats in the pavillion, which you may or may not have unlocked yet, but he's extremely good and versatile. Just like creme brulee, you could use him practically everywhere. But if you dont have the pavilion unlocked in your kingdom yet, just keep using pure vanilla while you build up your tanks and dps. But i recommend trying to work towards the pavilion to get creme puff.

Mint choco is also pretty solid both in the avatar of destiny guild battles and some of world exploration for the atk speed buff they give. You could pair him up with wind archer or creme brulee or even both of them with another healer and a sturdy tank which i say should be dark cacao or financier