So I've had this idea for a platformer fighting game and I'm having trouble coming up with the key binds
Obviously jump is z and attack is x and we have the four directional imputs, but then I want to add a dodge/parry, a strong attack and a special so does anyone have any ideas

Firstly, I'll just point out that "jump is z" shouldn't be the obvious pick for that genre. Literally every fighting game I've ever played has had jump on up.

That said, usually parry is forward pressed at the same time as an opponent's attack would hit. Dodge could just be a double tap on either forward or back, if you don't have running or quick hops. Otherwise, the go to input for that would be either pressing both (which would be king of fighters style) or down and both (melty blood), though the latter wouldn't work for pico-8 very well.

Special could also be done by pressing both if you don't use that for something else. Though, if you want more than one special, the smash brothers smash attack would work too. That's done by pressing a direction at the same time as an attack (as opposed to already having the direction held down).

Besides that, sequences of inputs are an option, but for a pico-8 audience I would recommend they be short. For example, back, forward, x wouldn't be too hard.

Very insightful @kimiyoribaka!

A lot of games with gravity (platformers) don't necessarily need to use up and down for movement control. Unless you use these for jump and, say, duck, you can consider them as direct inputs for other moves, or modifiers for your x/o inputs. So, for example, you could have:

Jump: Z
Attack: X
Dodge: Down+Z
Parry: Down+X
Special: Up+Z
Strong Atk: Up+X

I'm not sure about the last two (Especially Special on Up+Z unless it's a jump attack) but Castlevania uses up as a modifier for special weapon so I don't think Up+X is too out-there.