There's a partial list here of
types depicting
Constantine (but note that this is not the same as a list of
types issued by
Constantine) :
http://www.constantinethegreatcoins.com/types/If you are going to focus on
Constantine, then I'd strongly suggest
buying a copy of the book :
Roman Bronze Coins: From Paganism to Christianity 294-364 A.D.
by
Victor Failmezgerhttp://www.numibooks.com/book_info_page.php?id=239It's a great starting point, although unfortunately it emphasizes legends over
types and ignores who actually issued each
type. It has lots of coin photos which will be very useful.
Another very worthwhile, and inexpesive, booklet is :
The Pattern of Bronze Coinage under
Constantine Iby John
KentThis stops around 324 rather than the end of
Constantine's reign, but has the advantage of dividing the coins up by
mint and date so you can figure out who issued them. It complements the
Failmezger book, but is a decent starting point in of itself.
There's a copy on
eBay right now # 170202988196
In addition to what is published in the main references, there are also a few
types in more obscure references, and more recent finds that are unpublished. It'll be almost (or realistically, totally) impossible to collect a
complete set, but plently of fun trying!
Ben