Jigs & fixtures - The "is it a fixture or is it a jig" debate is made that much more tangled by the current interchangeable use of the terms. Suffice it to say, we don't have a dog in this fight. We'll just try to use the terms most commonly used.
Frame jig - Frame jigs run the gamut from $350 "it'll do for now" disposable (and flammable!) particle board versions, up to $5,000 rocket-science precision, aluminum and steel pieces of art, and of course, rock-solid, dependable work horses in between (we used to have a link to Arctos jigs, but that link is now dead. We're trying to find out what's up). Where you end up on this continuum will be determined mostly by how much money you have to spend. And let's not forget some killer DIY versions out there. We'd also like to point you to the amazing YouTube channel that Steve at Pithy Bikes has going on. You can kill hours watching him work through all sorts of cool stuff.
Fork jigs etc. - There are so many other jigs to add to the list that we'll try to keep it short. Fork jigs are a good thing to consider, as are stem jigs, canti-mount jigs, and many other things you may never have thought of. See some of the above frame jig sources for these ancillary items.
Heat source - If you want to braze, you'll need an oxy-acetylene set-up. If you want to TIG, you're best served by spending the money on a quality welding set-up (see your local welding supplier).
We'll get more into more of this stuff in the future, check back later.