I get asked ALL THE TIME what paints i use and it varies a lot from place to place whichever emulsions are available to colourmix. Although i am still very faithfull to many of the Dulux colours as a handful of them have become my "pallette" without realising.
But Valspar have been very kind to me in the past and sell 250ml masonry paint colourmixed for £2.25! cant argue with that.
Another brand i cant argue with is Polyvine varnish. their waterbased emulsion varnish is available in many diy and trade stores and is so damn easy to apply with a clean roller over almost anything i paint. Here are some photos 7 years apart of an exterior south facing wall in Camden London where i have applied the ( interior!) varnish to only just beyond the painted skulls.
This is not an endorsement although sure as hell sounds like one! i was just genuinely impressed with this!