Are there typical jokes formed by adding 之一 at the end of an otherwise innocuous sentence?
Pause before delivering a keyword is more like a tease, and tease can be funny at times but not always. It gets funnier when the twist is more surprising and striking
the difference between &quot;他是我见过最好的人&quot; and &quot;他是我见过最好的人……之一&quot; is not striking at all because  'the best' and 'one of the best' are both common phrases
'他是我的男朋友'  and '他是我的男朋友……之一' is better but it only reveals the speaker has more than one boyfriend and it is not a big twist
I would consider the following funny:
'你是唯一人選……之一' -- &quot;You are the only candidate... one of the only candidates&quot; (it is funny because there cannot be more than one 'only'. It implies the speaker told the same lie to everyone)
'他樂於助人……才怪' -- &quot;He loves to help people... is not possible&quot;
&quot;你女朋友一定會回來……跟你算賬&quot; -- &quot;Your girlfriend will definitely come back... to settle old scores with you&quot;
It may be funnier:  &quot;你女朋友一定會回來跟你……算賬&quot; &quot;Your girlfriend will definitely come back with you... to settle old scores (with you)&quot;