Not in the same way you get emulators, indeed even the slowdown stuff some cards have (or you inject with DSATM) works in a different way. The way emulators change speed is they don't care what rate they display frames at, obviously though by default they will go for 25, 30, 50, 60... or whatever the official rate for the thing they are emulating is as that will mean the game runs as it would on the original. Speeding this up or slowing this down then gets you turbo and slowdown.
There was a chip for one of the versions of DS that overclocked things a bit but it was never well developed.
You can hack specific games to do things like remove vblanks (usually at a cost of considerable graphical glitches), maybe overcook text speed (if it can be selected you might be able to force even faster), remove extraneous text/animations, remove cooldowns or tweak them to run faster (if the conventional animation moves 2 spaces then go to 4 sort of thing). Some of that is not terribly advanced hacking but you will have to approach it on a game by game basis.
If you are just grinding in pokemon though why not just generate them?
