There are 192 4-letter words starting with A in the ENABLE dictionary — 5% of all 3,903 words at this length. A is a one-point tile and the bag holds a lot of them, so these words are less about scoring than about shape: they are what clears a vowel-heavy rack, and in a daily guessing game they are how you test a vowel you have not placed yet.
The list divides into 25 groups by second letter, the largest being the 27 words with al. Scanning the right group is faster than reading the whole list, which is why it is broken up below rather than run alphabetically.
If you know more than one letter, this page stops being the fast way to find it. Enter what you have in the unscrambler — the Contains, Starts with and Ends with filters combine, and setting both length fields to 4 narrows this list to the handful your letters actually allow.
All 192 words, by second letter
AA… (2)
aahs aals
AB… (12)
abas abba abbe abed abet able ably abos abri abut abye abys