"Knock-Offs" (insight upgrade)
"You can always choose between a Mark and its Brand variant, if it has one."
If we ever get more "Brand" relics based on the Mark relics, it would be great to have a new insight upgrade that, whenever a Mark or Brand is spawned, lets you choose which version of the relic you would like to take! Maybe it could do this by changing the relic icon to be a half-black half-red version of the icon, and hovering over it with either your left or right hand would show you the description and icon of either the Mark version or the Brand version if it does have a brand variant, and grabbing it with that hand gives you that version!
Glutton's Brand
"For a cost (food item), use to deal an amount of damage to ||(or maybe inflict poison on?)|| nearby visible enemies"
Perk — Damages (and/or maybe poisons) nearby enemies.
Drawback — Does not actually consume the food for the player, the food item is wasted.
(When it picks what food item on you to use, held food items would be prioritised over stored food items, and the held/stored food on the brand's hand would be prioritised over the other hand)
(Damage would scale with the quality of the food item used)
Messenger's Brand
"For a cost (slowness effect), use to dash a short distance"
Perk — Can be used multiple times in succession, maybe up to 3 or 5?
Drawback — Doesn't dash as far as Messenger's Mark, and each successive use without waiting out the temporary slowness effect stacks the intensity and duration of the slowness debuff. It would never be overall faster for traversal than just walking, to avoid people spamming it a ton to get around which would get super repetitive.
(Just to clarify, by "slowness" i don't mean the slow-motion effect that a couple of relics use, but rather the movement speed debuff effect like what one of the arena curses uses)
Haggler's Brand
"For a cost (keys), use to teleport to the area merchant"
Perk — Teleports to the area merchant without needing to rack up the wild 50 kills the Haggler's Mark requires. Could be used as a convenient teleport back to the merchant multiple times in the same floor if you have the keys to spare?
Drawback — Costs 1 (or maybe several? Could be based on luck?) key to use.
Innocent's Brand
"For a cost (protection heart), use to summon wisps"
Perk — Summons wisps to help fight enemies. Maybe these wisps could be special and deal more damage than normal due to being more costly to acquire than other methods, like Door Chime, Sheet Music, or Silver Chime?
Drawback — Consumes protection hearts, the amount of wisps spawned could vary depending on the type though, for example Tortured Heart = 2, regular protection heart = 4, other willful hearts = 6 (and maybe it doesn't trigger their special effects when it takes them away?)