No player is irreplacable and as good as he was at points last season, I would ssay this goes for 37year old Ronaldo too. Still a great player, one of very very few who could claim to be any more than embarrasing last season in all honesty, but this is 37year old ROnaldo still.
One name I see mentioend a bit is Omishen who I cant comment on as not really seen. Other mentioning the likes of Antony.
For me firstly, forget replacing ROnaldo the legend and Ronaldo the player. The most important thing is we need to replace a STRIKER, especially as the only geniune long term replacement we are quite possibly losing too in Greenwood.
Martial forget about, Rashford isnt a striker and again he isnt the answer on the wing let alone up front.
We simply wont have a single striker, we need two! Is the discussion viable when we havent even signed a ventral midfielder yet and are so far not even heavily linked with a defensive one.
We probably need to sign two and wont sign one. Personally of the players I do know, none of the names mentioned a lot are the answer, people like Schik as a second option isnt bad.
I would go for two younger players myself with huge potential. Said a million times and rarely see anybody mention him.... Amine Giouri should be signed regardleess of Ronaldo going or not, for me a potential superstar.
The other one is also French. Ekitike looks a little gangly, a little raw, but I think there is huge potential and ability about him, not to the same level, but he does remind me of a youner Henry