Great ideas Gigi- you have given me some ideas!
Buliej- I have found making suggestions around birthdays/Christmas etc helpful to close family members. Like "I saw some wooden stacking blocks in target that I know x would love". Or I also suggest non-toy things like clothes (again I request non licenced or printed clothing), books (again, not TV or movie related texts), art materials etc
I think one needs to differentiate between the givers. So I am not worried about a one off birthday present for my chn from a friend at their party and wouldn't say anything to the parent (but recycle the gift if necessary or put it away or let them play with it until the novelty has worn off). However for grandparents, aunts, uncles etc then they will be repeatedly buying gifts over the years so it is worth saying something. A good idea is to type up a list of suitable toys/gifts ideas and give each of these people a copy. Some cheaper alternatives will soften it!! But I wouldn't try and control what grandparents buy for their own home other than to suggest ideas or simply say I prefer my child doesn't play with plastic. Homemade toys are great and grandparents might like to make these with the grandchildren as an activity. Same with your list- suggest home knitted toys, muslin playcloths, photobooks, etc- things that the givers can make themselves. People are often hesitant in making gifts as they are unsure as to how they will be received but if you make it clear you value those type of things, they can be lovely gifts. And very few people make things from plastic!