Having been in comic collecting for so long, I understand now that there are different levels of importance when it comes to defining key silver age comic issues. Personally, I group these key issues into the following:
Mega keys (first appearances of A class characters)
Keys (first appearance of B class characters)
Minor keys (first appearance of C class and below characters + other events)
Mega key silver age comic issue
The mega keys will include the first appearance of main characters:
Fantastic Four 1 (first appearance of fantastic four)
Avengers 1 (first appearance of avengers)
Hulk 1 (first appearance of hulk)
Amazing Fantasy 15 (first appearance of spider man)
Tales of Suspense 39 (first appearance of iron man)
Journey Into Mystery 83 ((first appearance of thor)
Avengers 4 (first silver age appearance of captain america)
These group of key silver age comics will probably never lose their importance. However, that does not mean no new issues can join their rank. In fact, Tales of Suspense 39 was a fairly recent addition due to the popularity of iron man movies. From an investment point of view, if we can spot the new mega key issues, then you will be looking at a healthy rate of return. The next mega key will probably come from the second group of key issues.
Key silver age comic issue
I classify first appearances of B class characters as key silver age comic issues. I will only list characters that have potential movie appearances as it is foreseeable that this might transform a B class character into A class if the movie becomes popular i.e. Iron Man. If you want to spot the next Mega key, this will be the list to look from:
Strange Tales 110 (first appearance of dr strange): This issue exploded in value when rumors of a Doctor Strange movie began spreading around more intensely in 2013. The word on the street is that Marvel wants to anchor Dr Strange as the iron man equivalent in its Phase 3 movies by exploring the magical side of Marvel through him. This made every speculator and investor scrambling to grab a copy and pushing the prices high up. However, if you think this will be the next mega key, there is still room for growth.
Tales to Astonish 27 (first appearance of ant man): Driven by a formal movie announcement, prices for a 3.0 have pass the 1k mark and is more expensive than strange tales 110. However, I do not think antman has the potential to become the next mega key. He is not the leader of any group and definitely not a key person to usher in a new dimension for Marvel. I could be totally wrong of course.
Fantastic Four 52 (first appearance of black panther): Again driven by movie rumors, prices for this issue have started climbing aggressively during the summer period. Potential wise, I regard this as the same level as antman. Black Panther is cool but nothing screams mega key for me. The only thing that puts black panther above antman is that he is at least the e-xking of Wakanda and current kind of the dead. Prices wise, I think there is potential to grow as there is no solid news to confirm the rumors. If there is any formal announcement, expect this to increase in value fast.
Avengers 57 (first appearance of vision): Vision is a well liked character during the height of his popularity, rivaling even spider man. It is good then that among the list, this issue is the most affordable as well. However, if any formal announcement is made, I expect its value might surpass that of the fantastic four 45.
Fantastic Four 4 (first silver age appearance of namor): The king of the seas is already an expensive issue with 3.0 condition going over $300. If namor was to make a movie appearance, I expect this to rival tales to astonish 27 in terms of price level. Will it translate to mega key? Probably not as namor character belongs to those ‘either hate or love him’ type, which polarizes fans.
Minor key silver age comic issues
Finally, we come to the last section of the group. This has the most number of issues to cover since it features C class characters and below but I will keep the selection small. More specifically, I will concentrate on a few characters that might have significant movie appearances which can increase their fan base.
Tales to astonish 13 (first appearance of grook). This is the wild card of the group. Prices for this issue has reached over 1k for 5.0 and above condition due to the scarcity of this comic. The character itself is unproven and might be a failed experiment in the movie. There is no way this issue will become the next mega key but it might become at least a key issue if the character becomes popular due to the movie. However, the language and ability limitation means Groot will always play second fiddle to someone else.
X men 4 (first appearance of scarlet witch and quicksilver): The mutant brother and sister team has been confirmed to appear in both avengers 2 and x men first class 2. Interesting, prices have increased but have not reach fever level as a 7.5 is still under 1k. This might be attributed to the limited fan base of the 2 characters as well as playing a second fiddle role in comic stories. Current, nothing in the movie will suggest that they will gain in importance so I expect the prices of this issue to move steadily with the movies and then to fall once the movies are over.
Fantastic four 45 (first appearance of Inhumans): More movie rumors, this has the most potential to become a true key as Marvel is shifting the Inhumans from an outsider to become strong players in the marvel universe. I believe this move is to build up momentum for the Inhumans movie that has not receive any formal confirmation yet. I expect this issue to become a top key issue if the movie is real as the king of the inhumans (black bolt) is a strong character that can become A-class in the future.
Journey into Mystery 103 (first appearance of enchantress): With the success of Loki at the movies, I expect there will be a thor 3 movie with the enchantress being a part of it. If that is the case, expect this issue to become a minor key. Unlike normal villains, enchantress has the potential to belong to those who can retain fan attention. For example, on comicbookresources.com, she has a fan thread that is already 100 pages long, which shows how many fans she has.
Let me know what you think.