A slightly odd, old-fashioned practice that I have always favoured as a long-term contractor is that favours, praise and rewards should be reserved for permanent members of staff, not contractors.
As a contractor, you receive your remuneration directly in the form of money, so you should not really need anything additional. Yes, public praise can be nice for your reputation and can help with securing future work, but I have found that it does not need to be displayed openly. Merely having a list of people for whom you have done excellent work and who remember that tends to be the best long-term reward. Public recognition further up the ranks is not really necessary.
Although this may sound like an odd, humble brag or slightly self-effacing view, it is one that has some basis in history. During and before the First World War, some military traditions treated medals and formal rewards as things intended primarily for career soldiers, where they could support rank, status and advancement. The thinking was that such honours were, in a sense, less useful when given to conscripted soldiers who would only be with the regiment for the duration of that conflict.
I have found that the same broad idea can help with contractor and permanent staff relations. Contractors should not really be receiving extra rewards, such as public praise or internal recognition, because they are already being rewarded through their rate and contract. That recognition is often better spent on permanent staff, for whom it can support morale, career development and a sense of belonging.
This is only a personal viewpoint, but it is one that has stood me in good stead.