There is a link for the Amex Platinum card offering a bonus of 100,000 Membership Rewards [OFFER EXPIRED] with a reasonable amount of minimum spend. The link shows up for everyone and you do not have to be targeted to apply. If you have your eye on an American Express Platinum card and have not had this version before, now is a great time to apply.
Here is the link (no longer working) which was posted on this reddit thread. See bottom of post on how to find the 100K welcome bonus.
If you are interested in the Amex Platinum card but this is not the right time to apply, you might still be able to find links offering an 100,000 welcome bonus at another time. Some people receive targeted offers of 100,000 all the time so for them this might not be a big deal. There are sometimes nontargeted links with an 100K welcome bonus found online but they are hit or miss and you have to use an incognito browser (sometimes with multiple attempts) to get these offers to show up.
Update: The link is no longer working. Here are some options for those that want to apply for an Amex Platinum card:
1) Hope to get targeted either by mail or check Cardmatch for 100K.
2) You might be able to find 100K by searching in incognito browser for American Express here.
3) Apply for the public offer which has been increased to 65,000 points. Terms Apply.