okkkkk....
Thats a massive question. Most decent part mods which are updated for 1.12.3 have some CTT compatibility, and oh my lord are their alot of these. Its not that hard to write your own patches though.
Most mods tell you if they are compatible or not
Ill give you a little list
All of the Near Future Suite (Made by the myth, the man, the legend, Nertea (Who is now part of the KSP 2 team))
Far Future Technologies (Also Nertea)
Heat Control (Needed if you want to use FFT, made by Nertea)
Stock alike Station Parts expansion Redux (again Nertea)
HabTech 2 (ISS Parts)
BDB (Bluedog Design Bereau, American Parts)
The Tantares Set (Russian parts)
Modular Kolonization System (MKS)
OPT spaceplane continued
Tundra Exploration
Airplane Plus
Mk2 Stockaike Expansion
Mk3 Stockalike Expansion
reDIRECT
Feline Utility Rovers
These next mods are NOT part mods, but much are loved and if you mod your game, you really should always use them
Restock
Restock+
Waterfall
Waterfall for Restock
Parallax 2.0
Scatter
AVP, SVE, or Spectra
Any planet pack (FFT has engines with an Isp of 600x more efficient than the nuke engines in stock KSP). I recommend Strange New Worlds, Sauwel System, Kcalbeloh System, Before Kerbin, After Kerbin, Beyond Home, The World Beyond, or even RSS if you are feeling adventurous. BUT A WARNING. ONLY USE 1 AT A TIME OR YOU WILL HAVE HORRIBLE PROBLEMS. Pick one and use it.
I hope this helps
And happy KSP-ing
Superluminal Gremlin's post in orbit changes was marked as the answer
my best guess without more info, and considering youve posted it in the modded help thread, is phantom forces. not much you can do.
Superluminal Gremlin's post in orbit changes was marked as the answer
my best guess without more info, and considering youve posted it in the modded help thread, is phantom forces. not much you can do.
Superluminal Gremlin's post in What mods are compadable w/ Community tech tree? was marked as the answer