Electro Harmonics makes the Holy Grail, which is a great spring reverb. Danelectro Spring King.
Hughes and Kettner Replex, which is a delay and reverb.
Danelectro Corned Beef reverb.
There are a few more vintage "Boutique" pedals out there, but they will cost you.
You can also look for an old Alesis MicroVerb, which is 1/3 of a rackspace, but it is great for having any type of reverb you want. Just velcro it to your amp.
There are not many good reverb pedals out there. Of course the best will be in rack units.
I hope this helps you find what your looking for.