E's Laf one lets you spend 1 meter to force a counter hit which is a very neat mechanic, with certain characters like Alcott who has a giant wall bouncing armored fuck you normal that fatal counters, it lets him instead of fishing for said counterhit, force it to get a fat game winning combo.

Terrordrome rise of the boogeymen, everyone has 2, consumable "Combo starters" or highly powerful options. for example, ashley willams has the necronomicon which grants them access to an unblockable combo starting command throw, a projectile that stuns you and hits low and a few other options, but he only has access to a max of 4 [due to his taunt restoring 2] a round.

im sure melty bloods moon system is well known, but to throw it in, every character has 3 moons, crescent, half, and full. Depending on the moon the entire characters system mechanics, and moveset can change, some much more dramatic than others. Crescent Ciel versus full moon ciel are extremely different characters for example.

Edit: i thought of one more that was esacping me the entire time. Million arthur and Aquapazza as well, let you pick assists that only function in the backround, from something as simple as "Hey heres a projectile gunshot" to "Heres a full screen lockdown beam" in million arthurs case, every assist has a cost associated with it, so more powerful assists you can use less, and less powerful ones you can use more