| Σ | # | Presentation | Description | Related |
| 5 | 30 | ⟨a, b | aabba=1⟩ | Infinite non-Abelian group | 40 iso |
| 5 | 43 | ⟨a, b | abba=b⟩ | Infinite cancellative non-commutative monoid | |
| 5 | 46 | ⟨a, b | aaa=bb⟩ | Infinite cancellative non-commutative monoid | |
| 5 | 53 | ⟨a, b | aba=bb⟩ | Infinite cancellative non-commutative monoid | |
| 6 | 91 | ⟨a, b | ababa=b⟩ | Infinite cancellative non-commutative monoid | 5 iso |
| 7 | 267 | ⟨a, b | abba=bab⟩ | Infinite cancellative non-commutative monoid | |
| 8 | 555 | ⟨a, b | abbba=bab⟩ | Infinite cancellative non-commutative monoid | |
| 9 | 1137 | ⟨a, b | abbbba=bab⟩ | Infinite cancellative non-commutative monoid | |
| 9 | 1262 | ⟨a, b | ababa=baab⟩ | Infinite cancellative non-commutative monoid | |
| 10 | 2361 | ⟨a, b | abbbbba=bab⟩ | Infinite cancellative non-commutative monoid | |
| 11 | 4887 | ⟨a, b | abbbbbba=bab⟩ | Infinite cancellative non-commutative monoid | |
| 11 | 5855 | ⟨a, b | abaaba=baaab⟩ | Infinite cancellative non-commutative monoid | |