Reference

Settings: many, including a variety of Ardas (the setting of the Silmarillion). 

Main templates: Bells and Maitimos

Prerequisites:

All prerequisites are optional but contain helpful context. They are all readable standalone.

Luminosity & Radiance is quite long and worth reading first. The other prerequisites listed are short (longest is Eclipse) and can probably be read interspersed with Silmaril itself.

Subcontinuity	Prerequisite(s)	Map of known worlds (made by phi)
Elentári	seidr and spear	-
Telperion	in which the prime directive	-
Defy Your Limitations	Daevinity	-
North	Bindings	Map 0 (post North)
East	Luminosity & Radiance	Map 1 (post East)
Shine	Geode	Map 2 (post Shine)
West	groundhog day	Map 3 (post West)
South	none	Map 4 (post South)
Kandrona	none	Map 5 (post Kandrona)
Southwest	Eclipse	Map 6 (post Southwest)
untitled 1	none	Map 7 (post untitled 1)
Unbreakable Vow	the first page of either Bluebell Flames or Witchlight	-
untitled 2	none	Map 8 (post untitled 2)
Disappear		Map 9 (post Disappear)
shard		-
Starstone		-

Spoilers:

Subcontinuity "West" contains major spoilers for Puella Magi Madoka Magica.