Main books written as standalones, but the characters repeatedly show up throughout the series and you get the most enjoyment out of reading them in order.
The Falling Stars Series
Falling Stars – Book 1: myBook.to/FallingStars1
Stellar Evolution – Novella 1.5: (not a standalone) myBook.to/StellarEvolution1
Hidden in the Stars (HITS) – Book 2: myBook.to/HITS1
Stellar Collision – Novella 2.5: (not a standalone) myBook.to/StellarCollision1
SNARE – Book 3: myBook.to/Snare1