There are several diploma colleges in Bihar.Some of the best colleges in bihar being:

• Buddha Institute Of Technology
• RP SHARMA INSTITUTE OF TECHNOLOGY
• Netaji Subhash Institute Of Technology
• Millia Institute
• Sandip University
• MIT Muzaffarpur.

These are some of the good diploma colleges with good faculty members.Hope it helps!!

• Netaji Subhash institue of technology
• New government polytechnic
• Millia Islamia of technology
• JP institue of technology
• Ganga memorial college of polytechnic
• Aryabhatta knowledge university
• Girija Devi polytechnic college
• Buddha polytechnic institute