Not all verbs come in transitive/intransitive pairs.
Quite a few intransitive verbs have no transitive counterpart. To name a few...
ある、[行]{い}く、[来]{く}る、[歩]{ある}く、[走]{はし}る、[座]{すわ}る、かみつく、そびえる、[響]{ひび}く etc...
行かせる, 来させる, 歩かせる etc. are causative forms (使役形), consisting of conjugated form 「行か」 + auxiliary 「せる」, conjugated form 「[来]{こ}」 + auxiliary 「させる」, etc.
... and quite a few transitive verbs have no intransitive copunterpart. To name a few...
[読]{よ}む、[話]{はな}す、[置]{お}く、[食]{た}べる、[殺]{ころ}す、[調]{しら}べる、[投]{な}げる、[蹴]{け}る、[打]{う}つ、もらう etc...
And, there're a few cases where the transitive verb and intransitive verb share the same form, such as in:
[開]{ひら}く -- ドアが[開]{ひら}く(intransitive) / ドアを[開]{ひら}く(transitive)
[閉]{と}じる -- まぶたが[閉]{と}じる(intransitive) / まぶたを[閉]{と}じる(transitive)