Global Trade Station

So recently I found my old pokemon folder and i started looking on ebay for more cards thinking i might get into collecting again and i found a Dark Dragonite going for +£100 on ebay buy it now.
not knowing anything really about cards i found out about error cards well i looked at my team rocket cards and found out i have all of the error cards myself (though im not sure about the dragonite one)
I have

6 non holo Dark Arbok cards and 2 holos with the "©1999-23000 Wizards"
4 non holo Dark Golbats and 2 holos with "Apply Weakness and Resistance" and "Pokémon.Apply"
3 Dark Vileplume cards that have a weakness to "Fighting instead of Fire"
7 Dark Rapidash cards with stats that do not have Length
19 Grimer cards that say "Poison Gas attack puts Pokémon to sleep"
1 Dark Raichu thats evolution box is colored light grey
then i have 2 Dark Dragonite cards one holo and one non holo

anyone know how much they are worth if anything? also how do you tell if the dragonite is an error card?
thanks

the dark dragonite error card is non holo and if i remember correctly the number on the bottom should have the holo number instead of the non-holo number.majority of those error cards arent worth alot the dark arbok is somewhat common.dark raichu was a secret rare in that set but now u wont be able to get alot for it.alot of the older cards have died down in value alot only specific ones bring in the big numbers.some of them are just errors that were never corrected