I'll be littering you'll be littering she'll be littering we'll be littering you'll be littering they'll be littering
Future perfect
I'll have littered you'll have littered she'll have littered we'll have littered you'll have littered they'll have littered
Future perfect continuous
I'll have been littering you'll have been littering she'll have been littering we'll have been littering you'll have been littering they'll have been littering
I'd be littering you'd be littering she'd be littering we'd be littering you'd be littering they'd be littering
Past
I'd have littered you'd have littered she'd have littered we'd have littered you'd have littered they'd have littered
Past continuous
I'd have been littering you'd have been littering she'd have been littering we'd have been littering you'd have been littering they'd have been littering