I'll be adding here all the tutorials I think are the best for this game, is really useful when you're a modder
Creating IPL and IDE files
3dsMax Plugins:
gtaforums.com/topic/907323-rel-kams-gta-scripts-2018-upd-31052020/
Difficulty: Easy
Animating textures in models
3dsMax Plugins:
gtaforums.com/topic/277798-3dmax-script-pack/
Difficulty: Easy - Medium
Adding night vertex colors for models.
3dsMax Plugins:
www.gtavision.com/index.php?section=downloads&site=download&id=3395
Difficulty: Medium
This is useful to add transition between grass and pavement (alpha blend).
Difficulty: Medium
Here is shown how to add Lights and Particles to models.
3dsMax Plugins and Tools:
www.gta-modding.com/area/file-515-dexx-tool.html
www.steve-m.com/downloads/tools/rwanalyze/
Difficulty: Easy - Medium
Here you can see how add new water segments.
3dsMax Plugins:
gtaforums.com/topic/928506-rel-gta-water-io/
www.gtagarage.com/mods/show.php?id=5781
Difficulty: Medium
Here is shown how to create a new dynamic doors.
3dsMax Plugins:
gtaforums.com/topic/907323-rel-kams-gta-scripts-2018-upd-31052020/
Difficulty: Easy
Remember that this will totally replace all the paths in GTA SA, so it is perfectly for a total conversions (you can't edit current paths)
3dsMax Plugins:
gtaforums.com/topic/283684-sa-path-tool/
Difficulty: Easy - Medium
These shadows are shown in the game when you select "High Graphics" options in the game.
3dsMax Plugins:
gtaforums.com/topic/907323-rel-kams-gta-scripts-2018-upd-31052020/
Difficulty: Easy - Medium
This is great to create new objects that can be liftable by player.
3dsMax Plugins:
gtaforums.com/topic/907323-rel-kams-gta-scripts-2018-upd-31052020/
Difficulty: Easy - Medium
For total conversions this is really useful, you can make a texture transparent.
3dsMax Plugins:
gtaforums.com/topic/907323-rel-kams-gta-scripts-2018-upd-31052020/
Difficulty: Easy - Medium
These videos (part 1 and part 2) shown how to create an animation for objects and how to add it into GTA SA.
This video show how to create a smooth animation for GTA SA using biped (I used this method to create the animations for my Spider-Man Mod).
3dsMax Plugins:
In the description of the videos.
Difficulty: Medium
This is great to give to the peds additional details.
Normal Map Plugin:
hotmist.ddo.jp/plugin/normalmap/index.html
gtaforums.com/topic/485241-normal-map-tutorial-for-sa/
Difficulty: Easy - Medium
This plugin works better for me. Test it by your own ;)
Normal Map Plugin:
gtaforums.com/topic/760083-normal-map-plugin-tools/
www.mixmods.com.br/2015/01/normal-map-by-dk-plugin-tools.html
Difficulty: Medium - Hard
Great tutorial for fixing MMD models and adding them into GTA SA
by J16D