Murder By Death (1976)
Slightly cheating, but I've always loved this silly spoof.
A group of world famous sleuths gather in accordance with a mystery host's wishes. What follows ... is fun if you know the various tropes at play here. Throw in some mild barbs here and there and we're off and running. The cast all play it to the hilt and whilst it's a bit slight after all is said and done, I'll watch this again for certain.
Ahem.
Philosophy Of A Knife next honest