Steven Erikson: are all gods ascendants? If you mean ascendant in the general sense of being very powerful, then yes. If you mean ascendant in terms of progression, then there are exceptions. Most of the animistic ones, for example (the totemic, tribal ones) derived from the act of worship, or the attribution of significance to a particular place.(Q and A with malazanempire No 2 (2003))

There were so many paths to godhood.  Kadaspala was certain of that.  So many paths, so many paths.  Refuse to die, refuse to surrender, refuse to die and refuse to surrender and that was one path, stumbled onto without true intent, without even wanting it, and these gods were the bemused ones, the reluctant ones.  They were best left alone, for to prod them awake was to risk apocalypse.  Reluctant power was the deadliest power of them all, for the anger behind it was long stoked.  Long stoked and stoked long and long, so best leave them leave them leave them alone.

Other gods were called into being and the nature of that call took countless forms.  A convulsion of natural forces, until the very sludge awakens.  Wherever discordant elements clashed, the possibility was born.  Life.  Intent.  Desire and need.  But these too were accidental things, inasmuch as anything could be accidental when all the particles necessary for creation abounded, as they surely did.  There were other ways of calling a god into being. (TtH)

From FoD :-

The Azathanai (Elder Gods):

Grizzin Farl*

Kilmandaros (fem)

Sechul Lath

K’rul

Errastas

Nightchill (fem)

Farander Tarag (fem)

T’riss

Caladan Brood