Based on our record, esp32 seems to be more popular. It has been mentiond 3 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Esp32.net has a bunch of additional references, projects, and places to gather information. Source: over 2 years ago
Closest thing is the ESP32 from Espressif Systems See ESP32 link for details. Since you specifically asked for open source, so some tinkering and compile is required. Source: almost 3 years ago
There's also many more dev boards, chips and modules listed here, though they may not necessarily have platformio IDs. Source: about 3 years ago
Intel NUC - Intel NUCs are available as Kits(Barebones), Boards(Mainbaord only) and as perconfigured Mini-PCs.
Intel NUC boards - Four-by-four inch Intel NUC boards come with a soldered-on processor.
Udoo x86 Ultra - Udoo x86 Ultra is a modern PC, known as the most powerful X86 maker board and an Arduino 101 compatible platform.
Lattepanda - Lattepanda is a complete windows 10 single board computer and first machine that comes pre-installed with a full edition of Windows 10 Home Edition so you can easily run all the powerful tools including NodeJs, Visual Studios and Processing etc.
ESPRESSObin - Electronics, Single Board Computer, and x86
MikroTik RouterOS - The main product of MikroTik is a Linux-based operating system known as MikroTik RouterOS.