The OMTech laser manual specifically warns against allowing clutter to accumulate atop the cabinet:
It is highly recommended to have an extra work table nearby in order to avoid placing objects on or directly adjacent to the machine, which could become a fire or laser hazard.
OMTech USB570c Cabinet Laser Engraver User Manual
The Basement Shop lacks the floor space for their recommended “extra work table”, so the laser cabinet now sports a pair of wings:
They’re a pair of those battered maple shelves, cut to fit the length of the cabinet:
They’re a convenient 9 inches wide, just right for general clutter. That stubby screwdriver encroaching on the lid shows I haven’t been entirely successful.
Each white shelf bracket has three self-tapping machine screws driven into the wood and a single 4 mm SHCS through a hole drilled into the cabinet with a nyloc nut & washer on the inside. If I understand the somewhat abbreviated instruction sticker correctly, I installed them upside-down in order to put the longer end under the wood where it would do the most good; they’re entirely rigid enough for the purpose.
Some of the same indoor urethane finish I slobbered on the gate signs tidied the sawed ends.
The Smell of Molten Projects in the Morning 
There is never enough horizontal surface.
Verily, Nature abhors a flat spot!