The first Marvel pendant to Green lantern was Doctor Spectrum.
Doctor Spectrum was originally introduced in 1969 a member of the Squadron Sinister, an evil pastiche of Justice League, where he was the stand-in for Green Lantern. Later, in 1971, Marvel invented a parallel Earth reminescent of the DC Universe, with a good version of the Squadron, now called Squadron Supreme, in the role of the Justice League (and a good Doctor Spectrum filling in for GT).
Later still, in 2004, the Squadron Supreme was rebooted with J. Michael Straczynski at the helm in the title Supreme Power and spin-offs, featuring yet another version of Doctor Spectrum.
There was also a female version at one point, introduced in 2005 in The Thunderbolts.
All versions of Doctor Spectrum derive their abilities from an alien gem called the Power Prism, worn on the back of the hand. It bestows on a host the ability to project and manipulate light energy in various colors; create light energy constructs of various shapes, sizes and colors; flight; protection from the rigors of space and the ability to become intangible. The Power Prism is vulnerable to ultra-violet light.
This article has information about these versions (and more) of Doctor Spectrum.
The original evil Doctor Spectrum
Squadron Supreme version
Supreme Power version
Female Doctor Spectrum