I have a solid collection of Richard Ellis - Ellis Animated First Day Covers. However he didn't stop producing FDCs until 1992. And even did an occasional cover after that.
I am interested in larger groups of Ellis FDCs from around 1980 until 1992 or anything later than that.
I am also occasionally looking for other Ellis FDCs - what do you have?
I have some scarce Ellis to trade especially his rarely seen event covers for the International Jim Beam Bottle Collectors Conventions. (He was their official cartoonist and was even on the Board of the organization for awhile.)
A check of eBay shows well over 950 listing, many specifically in your time frame. You might be able to connect with sellers by purchasing one of their and then doing follow-up correspondence to do bulk mail order purchases. There are some heavy listers.