Hmm.. it really depends on what kind of functionality that you are willing to replace. Generally speaking, there is NO exact match alternative to Clickfunnels, but depending on the exact functionality you might find some alternatives. Below I've listed some alternatives to some of Clickfunnels' internal tools:
While Actionetics tends to be quite a new auto-responding concept, with no exact match. You may still do well with other autoresponders such as Active Campaign and SendLane. In fact, there is even a fully free open source alternative known as Mautic. You may freely use Mautic to create campaigns and follow up series with your leads, but please keep in mind, It takes some technical skills to work with it, and it cannot be integrated with Clickfunnels.
2. Funnels Building
Maybe Infusionsoft is the only alternative of Clickfunnels when it comes to building and optimizing sales funnels, Though Infusionsoft tends to be more of a full high price tag CRM solution for small businesses, But it does funnels building as well.
Clickfunnels allows the ability to build membership areas and sell them through the same platform. In case you are looking for a membership area building alternative, then maybe Ever Lesson might work for you, though it seems to be closed as of the time I'm writing these lines.
4. E-commerce Solution (Shopping Cart)
Clickfunnels can be a great single product e-commerce solution. But If you are looking for a tool doing the same or better then Shopify + some 3rd party plugins will do just great.
Shopify without any paid 3rd party apps tends to be almost useless.
There are tons of e-commerce solutions (e.g. Magento, WooCommerce, PrestaShop...etc), but most of them are lacking the option of having one-click upsells like CF does.
5. Affiliates Managment (Backpack)
Clickfunnels has this feature known as Backpack, which allows you to have your own affiliates for your own products/services. For that, there are tons of services (aka. Affiliate Networks) that allow you to do the same (such as Clickbank and JVZoo), but they take a commission from your sales and are a bit limited in the way they work compared to what you can do with the Backpack.
Generally speaking, there is no exact alternative to all the things Clickfunnels does, except Infusionsoft which is a CRM system rather than a sales funnels platform.