The basic 2.4Ghz WIFI module is based on the W600 embedded WIFI SoC chip with a simple 12-pin interface. at 2mm pin spacing The unit overall is 12mm by 10mm and supports IEEE802.11b/g/n and AT commands.
The controller supports 2 UARTS with RTS and CTS, 2 SPI controller and an SPI controller. There is also some GPIO support. Bear in mind of course that this is limited by the number of available pins on the connector. 2 grounds, power, reset and antenna leave you with TX0, RX0, TX1, RX1, CTS and RTS, which then leaves one general purpose I/O bit. The unit could, according to SEEED, be used for intelligent home applications, wireless audio and video, smart toys, medical, industrial and other applications.
Vcc in this case is 3v3 and reset occurs at a low level. a 50r impedance antenna is required. Operating current is 110ma.
I’ll point you to this link for more info on connections and more - https://www.seeedstudio.com/Air602-WiFi-Module-p-3139.html
To do anything with this board you of course need a soldering iron and fine soldering skills – hence the development board which presents a USB interface and 0.1” centres connection options. The development board, like the basic WIFI board, is inexpensive. RX0 and TX0 are used for USB, leaving RX1 and TX1 along with RTS and CTS and one GPIO pin available at 0.1” centres. The development board also has an on-board antenna.
Now, whether any/all of this is enough to justify moving away from an ESP12 (for example Wemos D1) is another matter. I’ll leave that to the reader. Here’s the link for the dev. board. https://www.seeedstudio.com/Air602-WiFi-Development-Board-p-3140.html