Do you have any suggestion(s)?

suggestion是一个可数名词，其复数形式是在词尾加上s,例如：The teacher has some good suggestions on how to learn English.

不要加s。Can you think of any suggestion for effective language learning?
你能为有效地学习语言想一些建议吗

一般要说any suggestions,就像问Any questions？一样

要加s.any suggestions?any questions?any ideas?

不用s,除非用的是some。不过要注意名次是不是可数的。可属于不可数都可以用any,但是只有可数的能用some

Do you have any suggestion?
你有什么建议吗?
Do you have any suggestions?
你有什么建议吗?

都一样