See TeamLava's Guide to Gifting
Which confirms the gifting limits of sending 3 Gold per day and receiving 20 Gold per day, and which confirms the limit of receiving 20 'Mystic Maps' per day, and finally, that the 'Gifting Counter' resets at 12:00am Pacific Time every day.
Also, after a little research, I believe the maximum number of Mystic Maps you can receive per day is 21 (1 from Stormie's Park & 20 from other neighbors).
Refer: Is there a limit on Mystic Maps?
I can confirm that I usually receive 21 Mystic Maps per day.