In one of the tables I'm part of, we engaged in a discussion about an antimagic field being able to nullify the effects of an warlock's Devil's Sight because Eldritch Invocations are magical in nature (Player's Handbook, page 107 - emphasis mine):
In your study of occult lore, you have unearthed eldritch invocations, fragments of forbidden knowledge that imbue you with an abiding magical ability.
Nothing in its descriptions contradicts the only "hole" of the antimagic field description, that is:
Spells and other magical effects, except those created by an artifact or a deity are suppressed in the sphere and can't protrude into it.
The Sage Advice Compendium includes a list of questions to see if something is magical, then, that something is indeed blocked by an antimagic field (emphasis mine).
- Is it a magic item?
- Is it a spell? Or does it let you create the effects of a spell that’s mentioned in its description?
- Is it a spell attack?
- Is it fueled by the use of spell slots?
- Does its description say it’s magical?
Since the Eldritch Invocations feature description says they are magical, are all eldritch invocations nullified by an antimagic field?