Is there a defined standard for the identification of Phases in a service, feeders and branch circuits? We have use BLUE, RED, YELLOW tape in the past for feeders but I noticed a Master Electrician carrying an index card in his wallet with various color standards for different applications. Is there a code reference on this? or just secrets of the trade?

There is no standard that I know of. Here's what seems to be popular

Black, red 120/240 single phase
black, orange & blue 120/240 3 phase
black, red, blue 120/208 3 phase
brown, orange, yellow 480 volt 3 phase

Ditto, Tom.
Remember the Orange goes on the high leg of the 240 volt 3phase 4wire delta.

424.35 Marking of Heating Cables.
Each unit shall be marked with the identifying name or identification symbol, catalog number, and ratings in volts and watts or in volts and amperes.
Each unit length of heating cable shall have a permanent legible marking on each nonheating lead located within 75 mm (3 in.) of the terminal end. The lead wire shall have the following color identification to indicate the circuit voltage on which it is to be used:
(1) 120 volt, nominal — yellow
(2) 208 volt, nominal — blue
(3) 240 volt, nominal — red
(4) 277 volt, nominal — brown
(5) 480 volt, nominal — orange

Color code
Branch circuits, 210.4(D), 210.5
Conductors, 310.12, 504.80(C),
647.4(C)
Grounded conductor, 200.6
Grounding conductor, 250.119,
310.12(B), 400.23
Heating cables, 424.35
Higher voltage to ground
Feeders, 215.8
Panel boards, 408.3(E)
Sensitive electronic equip-ment,
647.4(C)
Service-entrance conductors,
230.56