Sources of Spell Immunity - or, "how many spells can one be immune to?"

[Quertus]

How many sources of individual spell immunity are there? How many individual spells can one be immune to? And what are their limitations (spell level, number of times… any limited by spell type?)?

Off hand, I can remember Ring of Counterspells, Spell Blade (1 word or two?), and the Spell Immunity spell.

And, of course, Epic spells.

Anything else for, "pick a particular spell to ignore"? Any limits on stacking? And what are the limits on each of these options?

[Khedrac]

shield makes one immune to magic missile

Also do you count freedom of movement which makes one immune to a lot of movement hampering spells (though not to those that have additional effects).
Similarly quite a few spells simply give a status (e.g. power word: stun) so anything that makes one immune to the status gives immunity to the spell.

[Crake]

Shapechanging into creatures with natural spell immunity gets you their spell immunity, though that's rather late game. Master of many forms could also work if you could find any creatures with Ex spell immunity that you're able to transform into.

[RNightstalker]

Chosen of Mystra template makes a character immune to one spell of each level, as well as a handful of other (types of) spells.

[Efrate]

If pf is on the table there is this.

https://www.d20pfsrd.com/magic/all-spells/s/aroden-s-spellbane/

Boost CL, get a few rods of greater extend, and go to town. You could do worse with your 9ths than pretty good immumity to stuff that shuts you down.