2 layers60 × 40 mm

B TPS630702-Brk-01Mbr R01
Boardoza/Boardoza_TPS630702_Buck-Boost_Converter_Breakout_Board
TPS630702 High-Efficiency Buck-Boost Converter for Adjustable Voltage Regulation Breakout Board.
35 parts5CC-BY-SA-4.0
KiCad boards from 2 GitHub repositories tagged “high-effeciency”, the most starred first; open any of them in PCBKit.

Boardoza/Boardoza_TPS630702_Buck-Boost_Converter_Breakout_Board
TPS630702 High-Efficiency Buck-Boost Converter for Adjustable Voltage Regulation Breakout Board.

mlab-modules/BATPOWER04
High-efficiency step-down converter based on the LM3485 PFET buck controller. Input voltage range is 4.5 V to 16 V.