For standard equipment, basically anything that's reocurring, not one time things should be fine.
That means Fludd would have to go and Luma because Luma is actually no longer aprt of his equipment but fire flower, mushroom, superstar, tanooki, mini mushroom, giga mushroom, etc should be fine, even the new mario powerups like ice flower (galaxy too i guess). Hammer is one of his iconic items, original game, wrecking crew, paper mario, paper mario 2, super paper, sticker, color, mario & luigi 1,2,3,4,5, etc, it's definitly one of his mains. It only doesnt appear in the platfrming games, and that's because of gameplay, it's a game first and foremost but if it aint a platfirmer it's usually his main weapon.
I'd say anything that appears in more then two games and something he didnt explicitly lose should be fine, with exceptions being brand new items that havent gotten a chance to appear in more then one or two games. Although Cappy would be standard for the time being as that's Mario as of his latest.