The link between cleric and deities is only a suggestion in 5e, not a hard rule (although it's certainly a house rule when I DM in the Forgotten Realms). Talos and Unberee would be pretty peeved if clerics of Shar started tossing lighting around.
PHB, Shar gets Knowledge and Trickery. You could make a case for Death, Arcana and Twilight from expansions.
Last edited by FrostyFardragon; 31/07/23 09:34 AM.