hey im not sure if i got you right, but before spending money for this thing i recommend this tool first: Sidescroller Tile Set Maker by MrLevRocks its free and made for sidescrollers which platformers obviously are.....
in case this tool aint the right one for you, you can check any tool from this list, all these tools are free;:
Procedural Tileset Generator by Donitz
Tilemap2Tileset 3.0 by YukkiTimmy
TilePipe - tileset pipeline tool by aleksandrbazhin
Isometric Tile Toolkit by Screaming Brain Studios
Tiled Map Editor by Thorbjørn Lindeijer
NEXXT studio 3.7.5 by FrankenGraphics
Tile Builder by Steven Colling
Unique Tile Finder by MrLevRocks
or in case you're already using aseprite i ran recommend a few extensions:
Aseprite Tile Bleeder by Mpdacey
Aseprite isometric converter by Noesteryo
a large collection of really useful lua scripts or extensions for aseprite but take care some are not free, but only very low price, which can be really useful if you use aseprite and would have to switch to another tool for certain actions, instead you can maybe pay 3-5 dollar to gain the extensions you may find useful, and this workflow savers a lot of time.....
there for instance is also a tile generator extensions: Tileset Generator for Aseprite by Toronja it costs exatly the same as the tool, this thread is about.......
New & popular tools tagged Aseprite - itch.io
in case you have more questions about tools or extensions or such things, ive spend a lot of time to get an rather good overview of all kind of tools as well as game-engines
best regards, love and peace....