I dont' know why there are no Corollas on this board, but the new ones do better than new civics and the older ones can't be that much worse. What about a 2 door Tercel from back in the day? That's prolly not too shabby. I guess more of these cars are in automatic form than Honda. I dunno--seems worth a look.
My neighbors used to have an old Mazda 323. Real basic car. Prolly like an '86 or '87. That thing was great on gas. So I'd say a real basic budget Mazda. You can use the
www.fueleconomy.gov and search different makes and models from the time period you are interested in.
I'd say any Japanese or really foreign vehicle is going to be better than American made for FE and I'm not just referring to their generally smaller size and motors--even them little American Makes just don't seem to have very sophisticated engines for saving fuel. But that's just my opinion.
Olderish Kias and Hyundais dont' seem to be very good either. But maybe late models have improved.
I know nothing of small Nissans Fuel Economy. If I had to choose a non Honda make, I'd probably go with Toyota (Corolla) or Mazda (323 or similarly small/budget). I may edit this post if I can think of or discover other sleepers.
EDIT
1998 Findings: City/Hwy. The following vehicles are 1998 Manual Transmission. All MPG are new EPA.
A regular civic gets 27/34.
An HX gets 30/39.
Mazda Protoge gets 26/33
Toyota Corolla gets 27/34 (same as regular civic)
Toyota Tercel gets 27/35. (I believe this is the CE trim)
Saturn SL and SC gets 24/36.
Hyundai Accent gets 25/33
Suzuki Esteem 26/33 but probably sister badge to the Mazda Protoge.
VW Jetta Diesel gets 33/44
Reply with roughly the year you are looking at and/or how much you are looking to spend and I will post more findings.
1999 Tercel gets 28/36 (CE trim I believe)
1997 Tercel gets 28/35 (I believe this is the CE trim)
1996 Tercel gets 29/36 (CE trim I think) That's not so far off '98 Civic HX territory.
2000 Toyota Echo gets 29/37 (the Automatic only gets 26/34)