The number of ancient coin types is far too large to collect them all, so many collectors seek coins that fit a "theme" they have in mind. Most of my collecting friends have several "mini-themes" going at once. I have long had a page: http://augustuscoins.com/ed/catalogs/themes.html about potential collecting themes, with advice for beginners and references to further information about them. Today I improved it with larger photos and a new example at the top. If you like ancient coins but don't know what to collect, I recommend you read the threads in this forum until something strikes you as especially interesting. You don't need my list to find a theme. However, my page lists numerous "themes" others have found interesting and illustrates one coin from each theme. Once again, the link is: http://augustuscoins.com/ed/catalogs/themes.html I encourage you to use this thread to mention (and illustrate) other potential themes or mini-themes.
My collecting interest for 75 years has been as found, circulating, working class coins. Save the nicest one you find. I have most of the circulation grade coins from the late 19th century and the 20th century. The closest I can get now is unclean ancient coins. Taking on these lots is as close as I can get to finding coins in circulation, in the wild as some may say. I have cleaned and identified over 200 in the past couple of years. Like finding them in my pocket, what you see is what you get. This theme works for me.