Most of the puzzles and forms shown on the Logelium pages are not new of course. Many people have worked on the polyform subject already. But I hope that I have added some new aspects. The following links are my source of inspiration and should be explicitly mentioned.
Disclaimer: I am in no way responsible for the content of any of the linked pages.
These pages are frequently updated and a central source of information about all and everything which is connected with puzzles. Furthermore there are lots of links to related subjects. Here I find new ideas quite often.
A virtually unexhaustable dictionary of mathematical knowledge.
Livio Zucca's »Remembrance of Software Past«
This is a firework of polyforms. Although there seem to be no updates since some years, its worth browsing again and again. Especially the pages about Doms inspired me to have a closer look.
This is an almost complete dictionary of polyforms. After some years the site comes to life again, and its nice to see now a multi language edition.
Miroslav Vicher's Puzzles Pages
You can find a number of unusual polyforms. For some puzzles complete series of convex forms are displayed. This inspired me to find all convex forms with Stomachion tiles.
Peter's Puzzle and Polyform Pages
Peter Esser did extensive research on some polyforms and wrote a solver. I found the 3D puzzles quite impressive. He put a lot of work into physically implementation of polyforms which you can see on some photos.
Geometric Puzzles in the Classroom
I like the designs of PolyArcs of Henri Picciotto. There you can find Logelium Solutions of Diarcs.
A tour of Archimedes' Stomachion
This article shed some light on mathematical aspects of the Stomachion. These are also transferable on other convex forms with Stomachion.
These pages are an incredibly detailed survey on polyforms constructed from tan shapes.
You find a big catalogue of puzzles. There are many polyforms, but also burr and others. The many given solution data served for verifying the Logelium solver.
Alfred Hoehn (German)
I like the connection of art and mathematics. Puzzles are only a side note. Here I found the idea, to transfer the principle of the Pythagoras triple to triangular grids. It was extremely interesting to apply this on Kite Pairs of DiDoms.
Mathematische Basteleien (German)
Under this smart motto you find a large collection of puzzles and other mathematical gadgets. There are plenty of formulas and explanations in a nice didactic presentation.