Well you could try the web sites of retailers who sell the things - you should get the features, size and an idea of the new price.
What to look for:
- incident light facility - these days usually an opalescent thing which slides over the sensor
- flash metering
- spot metering, if so the size of the spot - some are only around 1 degree coverage, this may sound ideal but needs a sighting system to point accurately
- size may be an issue, some of the spot meters with sighting systems are not as small as you might think
I have and (occasionally) use a Gossen Sixtomat digital meter which seems to be accurate, it's never let me down, the battery seems to last forever. Doesn't have flash or spot, does have a nice feature where you can hold down the button and scan across the scene to get an idea of the contrast within the scene. But I find digital readout meters aren't as intuitive as analogue (swinging needle) meters.
The reason I say "occasionally" is that I prefer to rely on the inbuilt TTL meter on the Olympus OM-3 and OM-4 cameras I use most of the time, for reasons of convenience as well as the multi-spot mode being very flexible and effective in difficult light.
What you would appear to want is one of the old-fashioned CdS meters that were popular about 30 years ago - sorry, I don't know if/where you can still get them, except on eBay where you need to watch out for old meters which require PX625 batteries which are no longer available.