Since nobody is answering I am pushing a little:
I would just go with using the Scale Curve to set following resolutions
16:9
1280x720
1366x768
1600x900
1920x1080
2048x1152
2560x1440
2880x1620
3200x1800
3840x2160
4096x2304
5120x2880
7680x4320
15360x8640
16:10
1280x800
1440x900
1680x1050
1920x1200
2560x1600
Also I come to the conclusion I should not ignore 4:3 aspect ratio because in the steam hardware survey there are quite a few 4:3 players
So following resolutions are missing:
1024 x 768 (4:3)
1280 x 768 (5:3)
1280 x 960 (4:3)
1280 x 1024 (5:4)
1600 x 1200 (4:3)
2560 x 1080 (21:9)
but I have no idea how I can make a UI that fits both 4:3 and Widescreen.
Also I have decided that 1024x768 is my absolute minimum. No lower resolution will be allowed.