Other than Greg Roman I haven't seen any names mentioned to possibly fill the void left by Jedd Fisch...
I've spent a great deal of time investigating and speculating as to who might make sense (not because I think I have great insight, but simply because I have nothing better to do). This is the list I've put together:
Cam Cameron - While you might have initially said "blah," he does have experience coaching WR's, experience at Michigan, a strong connection to the Harbaugh Family having coached with John and Jay in Baltimore. He would in many ways be kinda like the Greg Mattison of Offense: not likely to leave until he retires.
Jacob Peeler - He's currently Cal's "Inside Receivers Coach" and is considered one of the best recruiters in the country. Has developed a good amount of talent and is only 32 years old. He's been with Sonny Dykes for the past seven years so he's had his hands full coaching receivers in a pass heavy offense. He's a wild card as he doesn't have any direct connections to Harbaugh, but as we saw last year with Don Brown, that isn't necessarily a deterent.
John Morton - WR's coach for the New Orleans Saints. He served as Harbaugh's WR coach for his entire tenure with the 49ers and one year at San Diego. He's from Auburn Hills and also served as a long time assistant to Pete Carroll at USC so has plenty of experience in the recruiting game.
T.J. Weist - Worked for Harbaugh in an advisory role in year one at Michigan before joining Willie Taggart's staff at South Florida as Passing Game Coordinator/WR coach. Unsure if he'll be kept on at USF by Charlie Strong or go to Eugene with Taggart.
Please add on if there are any realistic names you think could be in play like Oakland.
No Chip Kelly's or Art Briles'.
EDIT to add a couple more names:
Jeff Faris - He's the WR coach at Duke and has been for the past two years despite being only 27-years-old (same age as JayBaugh). He coached Dylan McCaffrey's older brother Max to a record breaking season in 2015 so that could be an interesting connection to the program assuming the McCaffrey clan has nice things to say about him. He also coached Jamison Crowder in 2014 to a historic seasos.
Derron Montgomery - Worked with the Wide Receivers last year before leaving to become OC at New Mexico Highlands University. By all accounts he had a lot to do with the development of our receiving core last season.