Defense against 1.d4

1. ... d5 seems a bit boring for me and KID gets me into lots of cramped positions. Does anyone have a suggestion for what I can play instead?

What is 'boring' about it? If professionals players do not get bored after hundreds of games with it, neither should you.
You can chose: queen's gambit declined, slav defence, queen's gambit accepted.
In the QGD alone there is a choice: Tarrasch, Orthodox, Cambridge Springs, Bondarevsky, Meran, Shara-Henning...

Grunfeld maybe. I like d4 d5 because it's solid

d4 is known loss

@tpr I agree completely! I think that d4 d5 can lead to richest play of all variations in chess. Kasparov said that in an interwiev few years ago.

Tarrasch Defense is pretty good at lower levels, Slav Defense also is a great choice! Queen's Indian maybe..... Decision depends upon you :-)

@TheRoyalPlayer
There is the knight tango played by IM Opperwezen and CM Kingscrusher both tactical players who play razor sharp chess.
Also, 1.d4 b5 is not super sound but maybe worth looking at.
Then 1.d4 c5 to play Benko/Volga gambit is an idea as well.

I'm still looking too for a right answer to d4. I've tried Stonewall and Leningrad Dutch, QGA, KID, Semi Slav, Albin, Tango and even to answer d6 for every white first move, but I'm never satisfied.

@rederik79 What about QGD or NID+QID repertoire?

See if the Nimzo-Indian and Bogo-Indian defences suit you. You can also check the whole category E of the Encyclopedia of Chess Openings for good measure