Nettigo: Breadboard adapter for Raspberry Pi, T-shape [Yā nǔ shén]
2.1mm Barrel Jack Adapter - Breadboard Compatible - RobotShop
Amazon.com: Akozon 10Pcs USB Type A Female Socket USB Breakout Board 2.54mm Pitch Adapter Connector DIP for DIY USB Power Supply/breadboard Design : Electronics
Breadboard Adapter for Analog Discovery - Digilent
DB9 Breadboard and Prototype Adapters - Winford Engineering