That thread I started on Leak Stereo 70's etc got me thinking that there is quite a bit of gear out there which although of decent quality one barely ever hears about any more... and more rarely still is it ever suggested as a classic purchase.
I guess a classic example of such a scenario reversing would be old Japanese kit. Once you couldn't give it away but now it's suddenly desirable and fetching good money.
here's a few as a starter from me then:
1/ Leak solid state kit. It was expensive and well reviewed in it's day. The gems IMO are the Stereofetic tuner and the Delta 75 receiver. Stereofetic just as good as Quad FM3 and from same era. 2000 series amps to be avoided but tuners very good. Last 3000 series IIRC badge engineered Rotel. Stereo 30 plus, Stereo 70 and Delta 30 and 70 amps not bad but not that brilliant either. Fine for garage system etc and very cheap way of going retro. Delta stuff totally re-styled versions of earlier gear, made after Rank takeover. Look VERY different from earlier stuff but same internally.
2/ Armstrong 600 series. A range of amps and receivers and tuners in semi "slim line" cabinets. Not actually that slim but styling makes it look that way... Tuners are very good and the amps and receivers pretty good as well. Power amp and PSU section prone to faults BUT always one of 3-4 "stock faults" and easily repaired. A well sorted 625 receiver would get very close to an A&R A60 with T21 and at a fraction of the price.
3/ Tandberg amps, tuners and receivers. Famed for their tape recorders, Tandberg also made some very good (and very expensive new!) amps and tuners etc. From the Huldra gear to the TR2000 series and on to the last high end 3000 kit all very good indeed. Not as ignored as stuff above and going up in value...
4/ ReVox amps, tuners and receivers. Again known mainly for R2R recorders their later high end FM tuners were also always sought after but there are models from the 1970's which are very good performers and can be picked up relatively cheap. Try an A50 integrated amp for a pleasant surprise. 40WPC with very good MM phono stage and will blow an A&R A60 out of the water!
5/ Rogers Ravensbourne, A75 and A100 amps and matching tuners. Very good kit once highly recommended but now rarely heard of... Ravensbrook series was entry level and not as good. Personally I do not recommend their valve kit apart from the very rare top of the range stuff.
6/ Sonab and Scan-Dyna. Mainly the Sonab 4000 series and Scan-Dyna 2400 receiver. Very well regarded in its day and for good reasons.
There's loads more out there of course... short lived manufacturers such as Legend and Monogram who made high ish end gear in the UK for example.. or A&R's 200 series pre-power set up...
What have you got?