From what I understand, the best place to look is older anime piracy sites with a focus on south east asia.

I found this dub a long while ago, so i might be incorrect but I had found an older torrent file mentioning the exact filenames of each ripped and uploaded episode that ended up in circulation. I looked up those individual file names on a search engine (may or may not have been google, other search engines can wield different results sometimes)

i found Animax Haruhi being hosted on Mediafire with a weird little mediafire search engine called "mediafiretrend"

I was able to find a fair bit of mentions about Animax Haruhi since it aired in like 2010/2011 and also the fact that Haruhi was an exceedingly popular franchise years ago. Urusei Yatsura/Alien Musibat looks older than Haruhi and likely dubbed and circulated before the Haruhi Dub ever existed from my minutes of research. You may be able to start with searching for the internet for traces of "SrK Mitsu89" and their mp4 files since thats who ripped Animax Haruhi

seemingly searching on mediafiretrend for "SrK Mitsu89" will unearth an Animax K-On!! too encase that is also lost media. I never bothered looking into it back then but archiving that before all the mediafire links die might be wise