Recently Japanese grammar scholars are agreeing that it is impossible to analyze the conjugations of Japanese verbs using hiragana or katakana. Because many of their bases have consonant endings. So for example, it is incorrect to describe the conjugaison of 行く in this way; 行-く / 行-か-ない / 行-け-ば... The correct way is below; ik-u / ik-a-nai / ik-e-ba... And all verbs should be analyzed in this way; 見る→mir-u / 聞く→kik-u / 話す→hanas-u / 言う→i-u... So we can only say that all Japanese plain verbs have "u" sounds in their endings. And which consonant verbs take on their endings of bases are completely irregular.

yes, all verbs ending in く have a similarity... that they end in く. No other similarities.

As a native speaker, I have never thought about it. I roughly looked up why we have different verb-ending forms. However, there were many reasons in terms of linguistics, pronunciations as well as their historical developments, which I could not follow. I am not sure if there is some similarity in the same ending form (meanings?-maybe not. Conjugations could be similar). To me, your question seems similar to that English verbs have -sh (finish, dash, wash), ch (teach, catch, watch), other random things, etc. How can I remember "dash" and "wash" and distinguish them? I think remembering Japanese words including verbs for you is essential the same. Just remember them:)