What ways are there to disrupt spellcasting in 5e?

[Talionis]

Darkness can block line of sight. Silence stops spells with a verbal component. Anti Magic Field is a high level spell but does exactly what you want.

Mage Slayer feat is also useful. Also remember that at least half of all spells require concentration which can be broken with damage against a concentration check.

Interestingly a Shadow Monk has access to these spells and is Martial focused.