I have noticed that things that sometimes would be signs of failures in the lawn and garden, such as white clover in the lawn and Queen Anne's lace in the border are actually things that benefit the pollinators. Letting things be a little loose around the edges has its benefits.
Right now the bees are loving the white crepe myrtle. (I assume this is a pollen source for them.) I also have a few other things that the pollinators like. I made a bouquet of some, but there is plenty left outside for the bees and butterflies.
Some of the flowers here are butterfly weed, purple coneflower, oregano, yarrow, Queen Anne's lace, and hoary mountain mint.
I'm sure there are lots of online guides for choosing good plants for pollinators. Here is just one example: http://www.pollinator.org/guides
My coneflowers are from a packet of wildflowers I planted about 20 years ago.
As a side note, I thought it was fascinating that, according to the video I referenced above, the bumblebee loosens the pollen from tomato plants by vibrating its flight muscles at a frequency similar to the note C. Darling son said he was surprised it wasn't the note of "bee." Then he added, "I guess that bee was sharp." (B# is C.)
When I consider what bees do, I'll say they are sharp indeed!