The acts join headliners Stereophonics, Noel Gallagher's High Flying Birds and Craig David's TS5,
Other acts being added to the lineup inclue: Everything Everything, Shed Seven, The Big Moon, Nina Nesbitt, Fickle Friends High Hazels, Oddity Road and more.
2018 marks the first year that the festival is being held in Hillsborough Park, with multiple stages being put on at the same time in the park.
A spokesman for the festival said: "Once again proving itself to be a musical feast, Tramlines Festival today announces a second wave of acts to play its celebratory 10th edition.
"Taking place at the new location of Hillsborough Park in Sheffield from Friday 20th – Sunday 22nd July 2018, the worlds of indie, rock and roll, garage, rap, pop and hip hop all collide when these acts join the previously announced headliners Stereophonics, Noel Gallagher's High Flying Birds and Craig David’s TS5, plus Blossoms, De La Soul, Jake Bugg, Reverend And The Makers, Stefflon Don, The Sherlocks, Mabel, and tons more in its biggest lineup yet.
"This special installment of Tramlines comes with more festival-style entertainment than ever over four stages including a comedy lineup, pop up cinema, family area, and a brand new Leadmill Stage. The whole of Sheffield will be in party mode when they come together for this momentous version of Tramlines."
The first announcement saw Stereophonics, Noel Gallagher's High Flying Birds, Craig David’s TS5, Blossoms, De La Soul, Jake Bugg, Reverend and The Makers, Stefflon Don, The Sherlocks, Mabel, The Magic Gang, Coasts, Pale Waves, Gengahr, Naaz, Mullally, and Stereo Honey all announced.
Headlining Stage 2 on Saturday are multi-million record selling chart toppers, Clean Bandit.
The spokesman added: "Few acts have risen through the ranks as quickly as this three-piece, mixing dance music with classical in rousing new ways. From hits like ‘Rather Be’ to ‘Rockabye’ to ‘Symphony’, their crossover style is a favourite at festivals around the world and guaranteed to be a winner at Tramlines.
"Tramlines is thrilled to announce that the Mystery Jets will headline the Leadmill Stage on Friday night.
"The standout British band whose fusion of indie rock, post-punk, psychedelia and prog has made them firm favourites over the course of six albums and more recent singles like ‘Bubblegum’ as well as classics such as ‘The Boy Who Ran Away.’ T
"Then headlining the Leadmill Stage on Saturday are livewires Rat Boy who’ll be bringing more than just guitar music to Tramlines with their raucous live show and on-stage chemistry. Expect tracks from their debut album ‘Scum’ that the band brought to fruition with a little help from Blurs’ Damon Albarn and Graham Coxon.
"Also amongst the latest additions are local heroes Milburn in a not-to-be-missed appearance. Since reforming a couple of years back, the band have enjoyed an incredible couple of years, and have told festival organisers that this will be their “last show for a long time”! Support comes from indie innovators, The Big Moon, who return to Tramlines after a killer performance in 2017".
For tickets, go to www.tramlines.org.uk.