Hello and welcome, I'm waving from the Left Coast, Seattle area. I'm so glad to hear you want to design your own projects, for many people that is scary territory. For others of us, just the way we think.
I use graph paper and Electric Quilt myself, good luck on your search -- you might want to take note of this site which I use quite a lot:
https://www.incompetech.com/graphpaper/
Quilt design stuff is sort of in the middle, but I've used the dots and such too.
You might also check out this site, it has a quilt design section I've never used although I've used other portions of the site.
http://mywebquilter.com/