Thank you for the info, it will be vital in growing the game! I'll definitely make a more fleshed out tutorial in the future, I admit for now it's more of an information dump and can become overwhelming.
"Assist" makes so the assisted card buffs its stats by the same amount of the assisting card, and lasts until the end of the next turn, and "Bonus Attack" are just atk increases gained through effects, like Sol's or Luna's (Assist buff doesn't count towards this). I'll also definitely add tooltips for these keywords or ones that may explain more advanced rulings in the future!
Stay tuned ;)