Midfielder Fowler and striker Styche have both agreed one-year deals.
"We've been able to sign three very good players, I'm delighted with them," Rovers manager Dave Hockaday told BBC Radio Gloucestershire.
"Fowler is a warrior, he'll secure the middle of the park, Reece and Ross are very quick and are both goalscorers."
Fowler moved to the New Lawn from Salisbury in July 2009 but missed most of last season with an ankle injury, while Styche joined Rovers from Chasetown in January.
Meanwhile, Forest Green are still waiting for confirmation on which division they will be playing in next season.
Rovers were relegated from the Blue Square Premier but could be granted a reprieve as a result of Salisbury's demotion.
However the Whites are appealing against the punishment that was handed to them for failing to exit administration by the second Saturday in May.
"We're in limbo," said Hockaday. It's very frustrating and I'd be the same if I was a player, I'd want to know league I'd be playing in."
"I obviously need to know as regards the budget I've got and obviously some players will be more willing to come if we're in the Premier, rather than the league below."
Source: BBC Sport
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