Since this is probably "not politics" im putting it here.
Some statistics to keep in mind that i compiled from this list:
Nearly 78% of bias in Wikipedia's "Reliable Sources" is a left-leaning bias.
Left leaning bias is 3.5 times more prevalent than right-leaning bias in Wikipedia's "Reliable Sources".
Out of all of their "Deprecated" sources, only 1 is classified as left by MediaBiasFactCheck
Next I might do their "Generally Unreliable" list.