The following spells contain the keywords "shadow" or "shadowfell" in their description.
PHB:
Creation, p. 229.
Demi Plane, p. 231.
Dispel Evil and Good, p. 233-234.
Forbiddance, p. 243.
Pass Without Trace, p. 243.
Vampiric Touch, p. 284.
XGtE:
Illusory Dragon, p 157.
Shadow Blade, p. 164.
Shadow of Moil, p. 164.
Summon Greater Demon p. 166.
I have searched through every spell in the PHB, the XGtE, the EE and the SCag.
My keyword search was done manually, and I have searched through each of the four books by flipping through the pages and reading through the spell description of every single spell throughout the entirety of the Players Handbook, Elemental Evil, Xanathars Guide To Everything and the Sword Coast Adventurer's Guide.
Thanks to IT Alex and Someone_Evil for reminding me to specify this last paragraph of my method used which further explains how the keyword search functions that I employed.
Further notice:
You are trying to build a character that thematically uses the Shadow and the Shadowfell, so it is likely that you want insight into how the Shadowfell affects creatures and the abilities of creatures. The following resources help you with that (this paragraph got added thanks to NautArch to make it more explicit on why you want to be informed about the information provided, in case that the first line and the rest of the next paragraph with the information included is not sufficient).
To gain an insight into how the Shadowfell affects creatures and their abilities read the Shadowfell DMG p. 51-52 and Planar Categories DMG p 43, and then compare Deva MM p. 15-16, Darkmantles MM p. 46, Manes MM p. 56 (also refer to Sings of Corruption MM p. 50).
The Dragon, Shadow and Shadow Dragon Template MM 84-85 are easily compared to other variants Dragons MM p. 86-118.
Shadowfell DMG p. 51-52:
These creatures are native to the Shadowfell: Undead, Cloakers, Darkmantles, Shadow Dragons, and
other creatures that thrive in the gloom
While Deva act as messengers in the Shadowfell, Manes are naturally part of lower Planes. Whether the twisted Shadowfell has an evil alignment or not is unclear.