These are some color themes that I am fond of.
Yellow
Hex #FAEE16
Purple
Hex #6A3FBA
Royal Purple
Hex #6617FA
Dim Yellow
Hex #A5A046
Dim Purple
Hex #5A487A
Robin Blue
Hex #29D3FF
Brownish Orange
Hex #BF854E
Orange
Hex #FE8F28
Steel blue
Hex #5498AA
Brown
Hex #806954
Dim Blue
Hex #2972CC
Blue Grey
Hex #3D6799
Lighter Blue
Hex #0073FF
Grey Blue
Hex #3D5066
Dark Blue Grey
Hex #292D33
Hex #004d33 Dark Green background
Hex #DFE9E6 Lightest shade for text
Hex #4D0019 Crimson border color
Hex #0090FF Azure Blue background
Hex #DFEFFF Shade for text color
Hex #FF8000 Orange border color
Hex #606060 Gim Grey background
Hex #EBEBEB Lightest shade for Text color
Hex #000000 Black border color
Linear Gradient: Red, Purple, Gold
-45deg, #CE1032 0%, #7626A4 50%, #C59237 100%
-45deg, #CE1032 0%, #7626A4 50%, #C59237 100%
135deg, #CE1032 0%, #7626A4 50%, #C59237 100%
Linear Gradient: Teal, Purple, Dark Blue
top, #18CADB 0%, #4A38A4 50%, #0B0982 100%
top, #18CADB 0%, #4A38A4 50%, #0B0982 100%
to bottom, #18CADB 0%, #4A38A4 50%, #0B0982 100%