The display of Saleae Logic LA uses the colours of the Saleae standard probe cable. However, I have a clone unit that uses a 2x5 pin header instead of their cable layout, so I use a Bus Pirate probe cable instead, which uses the colours brown/red/.../grey instead of Saleae's black/brown/.../violet. The unit itself is also labeled "ch1" to "ch8" instead of Saleae's 0 to 7, which goes alongside these other colours.
It would be useful if the Logic decoder view could remember when I'd changed the colours and labels of these channels for next time it runs.
Out of curiosity, I did some analysis on default colours for oscilloscope channels (4 are assumed for the following unless noted):
Tektronix/Hantek/Micsig/Atten/Tonghui/Rigol: Yellow/Cyan (Green in certain earlier Hantek)/Magenta (Green in certain earlier Hantek)/Green (Indigo in Rigol) - Atten and Tonghui currently do not manufacture units with more than two channels
Pico: Blue/Red/Green/Yellow (and for 8 channel units, Purple/Grey/Cyan/Magenta)
Rohde & Schwarz: Yellow/Green/Orange/Purple
From this analysis, Tektronix is the most popular colour scheme - if not implemented, Sigrok should include presets for oscilloscope trace colour schemes corresponding to the manufacturers on this list (and others not listed here).