So I did some pad swapping on these today. I compared stock pads to Dekoni X00 sheepskin and Accessory House Global (AHG) lambskin pads. It seems that both of these pads adds a bit to the lower mid range, warming up the sound a bit which I find nice. The Dekoni pads are the best for reducing the sharp treble but they also seem to reduce the sub-bass a bit. Overall they are good but not really my preferred choice, especially since they reduce the sound stage a bit as well. The AHG pads are what I’m going to be using going forward. These reduce the treble, but not as much, so it could still possibly be a problem for some (only those who are properly treble sensitive imo). They don’t reduce the sub-bass any and still warm up the lower mid range nicely. The AHG pads are also the most comfortable by far. They are deeper than the stock pads and have a larger ear hole than the Dekoni pads. The sound stage is also comparable to the stock pads (possibly a touch smaller but nothing that I would call noticeable for most people). The imaging with all the pads is unchanged as far as I could tell.
In conclusion, if you want a more comfortable, warmer, and less sharp DT-770, get the AHG pads. The Dekoni pads are still good but they are expensive and need to be special ordered via email, so I cant really recommend. The AHG pads are ~$30 on amazon.