Where is there a list of the URL functions?

QuickBase has two sets of URL "actions". Those actions like "a=dr" (display record), "a=er" (edit record) and "a=nwr" (new record) are "native" actions meaning that they appear in the Address Bar and represent the primary actions of the normal GUI interface. I don't know of any public list of these actions but they are so visible that everyone uses them in crafting formula URLs and hyperlinks.

The second set of actions are associated with the HTTP API and they typically are referenced as "act=API_AddRecord" or "act=API_EditRecord". The documentation for the HTTP API is here:

https://help.quickbase.com/api-guide/index.html

For the most part the HTTP API methods (with only a couple of exceptions) are not displayed in the Address Bar as they don't represent human readable content (they display XML in most cases). This set of URLs are used for scripting automation of some sort either from an external server or via script in your browser. 

One difference between the two sets of "actions" is that the HTTP API urls are documented whereas the native actions are not "documented" (even though they are 100% visible and used by every user).

They two types of "actions" come together sometimes in complicated formula URLs that string together several actions and avoid ever displaying XML by including the rdr parameter which immediately redirects away from an XML response to a human readable page.

Mark Shnier is probably the best person to describe the chaining of these two types of URL actions together as he sort of standardized the formula URL into this "canonical form":

var text URLONE = ...;
var text URLTWO = ...;
var text URLTHREE = ...;
$URLONE
& "&rdr=" & URLEncode($URLTWO)
& URLEncode("&rdr=" & URLEncode($URLTHREE))

There is much more to be said so I would continue the discussion if you have additional questions or if their are other perspectives.