Salut Philippe, cousin québécois 😉
I suppose you have XP11. Welcome! Me too I installed XP 11 recently (but I keep P3D).
AS for XP should be out soon now.
Looks like you have what you need regarding airliners. Otherwise, if needed there is also the Flight Factor A320 and 777, and also Toliss A319.
For light aircrafts I recommend Airfoil Labs C172.
Check also the Reality Expansion Pack https://www.simcoders.com/reality-expansion-pack/overview It is a kind of Accusim for XP.
For helicopter I recommend the Dreamfoil Bell 407.
Regarding sceneries, personally I find that the default scenery is quite good and immersive so I decided to stay with it. I am not aware of a equivalent of Global FTX etc. for XP.
For textures, shaders, moon, water... I don't know since I'm not interested in such utilities at this time.
For flight planning, Goodway is very famous in the XP community. Personally I had already FSTramp for P3D which work also for XP.
If you are looking for a view management utility, something like EZDok or Chase Plane for P3D, then on XP, X-Camera is the way to go.