In 1986, the combined share of the six classic [major movie studios]—at that point Paramount, Warner Bros., Columbia, Universal, Fox, and MGM/UA—fell to 64%, the lowest since the beginning of the Golden Age. Disney was in third place, behind only Paramount and Warners. Even including it as a seventh major and adding its 10% share, the majors' control of the North American market was at a historic ebb. Orion, now completely independent of Warner Bros., and Tri-Star were well positioned as mini-majors, each with North American market shares of around 6% and regarded by industry observers as "fully competitive with the majors". Smaller independents garnered 13%—more than any studio aside from Paramount. In 1964, by comparison, all of the companies beside the then seven majors and Disney had combined for a grand total of 1%. . . .
Box-office domination was fully restored: in 2006, the six major movie conglomerates combined for 89.8% of the North American market; Lionsgate and Weinstein were almost exactly half as successful as their 1986 mini-major counterparts, sharing 6.1%; MGM came in at 1.8%; and all of the remaining independent companies split a pool totalling 2.3%. [Wikipedia]
And here we had always associated the hey-day of "indie films" with the '90s. (The quote is from the article on major film studios -- it's skipped over in the one on independent studios.) But it shouldn't be too surprising if we think of music from independent record labels, which also were at their peak influence from the later 1970s through the very early '90s, with I.R.S. and Chrysalis Records being the counterparts to Orion Pictures.
It's really the last 20 years that have seen massive consolidation within the entertainment industry, although we've heard the "Greed is good" line so many times that we've forgotten that the go-go '80s saw The Little Guy at his most powerful in popular culture, even if he was losing ground in wealth equality.
There really are too many to list, but here are just a few iconic movies from the halcyon days of indie film (some are real surprises):
The Texas Chainsaw Massacre
The Rambo trilogy
The Terminator, and T2
Hannah and Her Sisters
Crimes and Misdemeanors
Silence of the Lambs
A Nightmare on Elm Street
This is Spinal Tap
...plus a lot of guilty pleasures like Bill & Ted's Excellent Adventure, Lethal Weapon, Commando, Kickboxer, Cobra, Bloodsport, etc.
Strange as it is to believe, not so long ago indie studios were pumping out instant classics instead of already-forgot-about-'ems.