Frankly for Anubias only I would not bother with fertilizers, they get most of what they need from the fish food/metabolism and water changes. If you have specific problems it helps to know which problems and remedy only those.
However if you want to be sure and an easy way, you could get Seachem Flourish, JBL Florapol ( also has a lot of K and traces), Easy Life line or Tropica Plant Fertilizer. You could also make your own solution for K from K2SO4. As Anubias are mainly slow growers, I do not see there is a risk of running low on traces really.
On hiatus till later this year