Controllers with a regular size often correlate with moderate weight, and they should fit on most laps without having to squeeze one’s legs together.
You can buy the PadBox GS preinstalled with a non-split or split D-pad, and it's good for fighting games & other genres.
We can rave on and on about the benefits of the MS1, but its selling point is its unique right thumb button placement.
The RC-OF1 is a variant of the OFOF1 chassis design by Rana Labs, so it features charm holes in all four corners.
If you don't need 16 or more buttons: the VSLAB VSNOVA N14 is a fine option with chamfered acrylic, customizable art, and cool LED.
The Split is divided into two halves connected through a coiled detachable cable—and should be compatible with future modules by Ultra Arcade.
The TIKITAKA M3 doesn't have 16 buttons. It has 17, and the 17th button is a rare fully sized start button on the top panel's upper left.
If ergonomic controllers make your hands too upright, consider the Maestro that only tilts your hands at a slight angle.
At a first glance, you may think this is a DOIO controller, but in reality—this is the NLOFIN NLHX-ET01: a 16 button controller with LED.