There has been no evidence presented by the intelligence community, only allegations. The so called classified "evidence" has not been presented for two reasons:
1. Digital forensics is unreliable when dealing with intelligence agencies with multi-billion dollar budgets. Any state-level hacking never leaves traces behind - the traces left are intentionally designed to mislead forensic investigations.
2. The intelligence community understands that the evidence is not sufficient and therefore is using the "classified" excuse to withhold the information.
Is it feasible that Russia influenced the election? Yes. However, many would suggest that this is a political deflection tactic from the democrats to shift the blame onto another entity. Political scientists have long understood how politicians use manipulation to prevent a reputation from being demolished. I would refrain from calling such skepticism as a "conspiracy theory".
Another controversial subject is the murder of Seth Rich who received attention from WikiLeaks after his death and his involvement in the DNC. Seth was a computer programmer and had technically knowledge which would explain why many people believe he was the source of the leaks.
WikiLeaks cannot reveal the sources of their publications for good reason, even after a source has potentially being murdered. So naturally, WikiLeaks cannot confirm whether Seth Rich was involved. But the WikiLeaks reward of 20,000 to assist with his murder investigation spoke for itself and cannot be regarded as another "conspiracy", as his involvement is extremely likely.