How to Choose a Scale By Chord Type
If you're after a major type sound or a scale that will work over a major chord, then check out the following scale pages:
On these pages, you'll find an extensive selection of pentatonic scales with the main ingredient for a major scale: a major third. Generally speaking, if a scale has a major third in it, it will work over a major type chord (including maj7, maj9, maj11 etc.). It's up to you to then try them out to see which one(s) you like the sound of.
Natural 7 or b7?
One thing to watch out for if you're looking for a major type pentatonic scale to play over a strictly major chord is the kind of seventh it contains. Major chords usually contain a natural 7, so you may want to choose scales with a major third (3) and a natural seventh (7) to avoid the b7 clashing with the 7 in the chord you're playing over.
If you're looking for a dominant sound, you will want that major third flat seventh combination as this defines the dominant sound found in chords such as 7, 11, 13 and altered dominant chords such as the famous 7#9 or 'Hendrix' chord.
If you're after a minor sound, you'll want to look for scales that contain a minor third (b3) as this is the defining interval for a minor scale/sound. Here the b7 or 7 option will give you two very different sounds, with the 7 sounding a little more eastern than its rockier counterpart, the b7. You'll notice that you can darken the sound by choosing scales that contained flatted intervals such as the b2, b6 and even the b5.
Scales with No Third
Another option, as far as scales for soloing over chords goes, is to look for scales with no third. This means that theoretically they can be played over major, minor or dominant chords as due to the lack of a third, there's no way to say whether it's a major, minor or dominant scale. You can find these scales starting around here.