This simple mod adds Nether and End Towers to Towers of the Wild mod, which only adds structures to the overworld. However, it has no shared code, data or assets, which allows you to run this on its own anyway.
# On Forge, compatible with both Towers of the Wild and Towers of the Wild: Reloaded. On Fabric, compatible with Towers of the Wild: Reworked.
# Compatible with Waystones mod. If enabled, all towers generate a waystone on top. This can be disabled on the config file. On Fabric, it's compatible with Fabric Waystones, too.
# Separation and Spacing can be configured to tweak rarity.
# Loot tables can be tweaked by datapacks.
# Completely server-side.
# Can be used without Towers of the Wild as a standalone mod.
Credits
Credits to idrae_ for the original mod idea, Towers of the Wild (although original code, data or assets were not used on this mod).
Additional thanks to TelepathicGrunt for their structure tutorial, to Commoble for their ConfigHelper (on Forge), and to xPand4B, who created the Fabric version of Towers of the Wild (licenced under MIT licence at the time of writing). Certain lines of code from xPand4B (specifically from here) were used to solve author discrepancies when integrating Waystones compatibility.
Images