For the "8BitDo pro 2" gamepad:
Go to the page
https://pastebin.com/HnT7Ng9N
press "download" and save the file as "8BitDo Pro2.xml".

Note1: make sure your 8BitDo pro 2 has 2.1 firmware or later running. Or the palm triggers may not work. (AFAIK they work since 2.0 firmware.)
You can update firmware thru the official firmware updater tool:
https://support.8bitdo.com/firmware-updater.html

Note2: Please switch the gamepads mode toggle button on the back of the controller to [D].

For the "Wii U Pro" gamepad:

(Note:you need to have "mayflash wii u pro adapter" connected to the PC for this to work. And set the mode to [D] on it.
Here is the Link to amazon [www.amazon.com], just so that you know how the adapter looks.) (You can connect total of 4 "WiiU Pro" gamepads this way.)

Go to the page
https://pastebin.com/n3wMPUw6
press "download" and save the file as "WiiUpro.xml".

Now.
Go to where your game is installed (where "TowerFall.exe" file is).
There open the \Gamepad_Config folder and copy the .xml file that you need there. Or just both files.

Done.

Q: Why do I need specific xml config file for my 8BitDo Pro2? Gamepad is already working when I set it in X-input mode.
A: 1) This will enable 2 palm trigger buttons. Left palm trigger for additional "arrow switch" button and the right palm trigger will work as additional "dodge" button.
2) All the in-game button prompts will be actually correct. For example - your gamepad's layout is displayed when you start the game and start your first match.
3) Proper naming of your gamepad. Its easier to recognize your gamepad in the character select menu when its says "8BitDo Pro2(D)" rather than "???".
4) You can more transparently tweak your gamepad controls by opening that specific .xml file. Rather than changing default config file "Default.xml". Which the game will use when it will not recognize your gamepad.
5) Better button mapping. Some buttons are awkward to use by the default. For example A and B buttons are switched positions and plenty of users are used to A being down (like on Xbox gamepad) and press B by mistake - this often results in exiting the character selection menu during the match setup. When 4 players often press "back/cancel" by mistake this creates a lot of mess for the match.

Q: How did you create those .xml files?
A: I wrote them in the notepad. There are already other guides explaining how to do it in detail:
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=242533486
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=447092671
But if you have these gamepads you can save yourself 1-2 hours and just copy the .xml files over. Instead of doing it by yourself from scratch.