lol
Let's see... I don't need any of these, but some price checks... Unfortunately rubble is way down off its peak prices; these are what I'd expect to pay today. (And just a note for anyone with rubble on vendors on Atlantic at the moments... the reason I keep seeing the same lower-end rubbles on the same vendors day after day for months not selling is because you're overpriced... Drop your prices already

)
Mostly I'd agree with Ducan, though these ones I'd price a little differently:
1. Nice wall piece. Figure 6 to 8m; one of the few rubbles that seems to have increasing demand these days.
2. 4 to 6m
3/14/15/16/18 the smaller pieces tend to be on the low end of that, more in the 100-200 range. #15 figure 250k-300k.
8 That one's one of the rarer mushrooms, and in more demand than the smaller stackable one; I'd put it on the higher end for a mushroom, 8m or so.
9 and 26 500k each,
maybe a slight premium for #9, which is a slightly more rare color
10 and 11 both look to be the black hue; a slow sale in any case, but 1m each to the right buyer
17 The picnic centers tend to run in the 3-5m range these days. The \\\ ones on the lower end of that, while the /// seem to be on the higher end, just in terms of demand
25 Very little demand, 25-50k
All the other plants, figure 100 to 500k, depending on which shard and where you're selling
EDIT: I'd note, these prices are based on Atlantic; my experiences with rubble on Drach have been that there seems to be little demand for it on that server.