Diphthongs formed by a vowel and a consonant are the following:

al, am, an, ar
el, em, en, er
il, im, in, ir
ul, um, un, ur
ol, om, on, or (these four came to Lithuanian from other languages)

Diphthongs formed by two vowels are the following:

ai, au, ei, ie, ui, uo
oi, eu, ou (these three came to Lithuanian from other languages)