Ibsen
Ibsen photonics produces small spectrometers that integrate a grating, a sensor and electronics. The sensor seems to usually be Hamamatsu. This is cool, but is in essence what I have in my homebuilt spectrometer.
The most interesting spectrometers at a first glance seems to be:
PEBBLE Ultra Compact OEM Spectrometers, and the product sheet. This is a miniature spectrometer with Wavelength Range 380-850 nm. In July 2020 Ibsen announced that it would become available as a PEBBLE evaluation package mounted on a breakout board. The cost was set to 2300 € (2660 $).
Compact and cost-efficient OEM spectrometer modules for the VIS-NIR range, and the product sheet. 475-1100 nm
In July 2020 Ibsen introduced a new FREEDOM VIS FSV-101 spectrometer with Wavelength Range 360 to 830 nm. The central part of the spectrometer is a Hamamatsu S11639 CMOS detector. Integrated with an electronic circuit, or breakout board, with an Arduino board and all peripherals and software costs 2000 € (2260 $).