The formula C₅H₁₂ belongs to a saturated alkane, therefore, it cannot have cycles or double bonds.

Alcohols that do not have chirality (without asymmetric carbons) are:

 

 

Chiral alcohols (have asymmetric carbons) are:

 

 

Ethers are also isomers with the formula C₅H₁₂ , but do not have chiral centers.

 

 

If you find any other isomers, post them in the stereochemistry forum.